When he shall come to be glorified in his saints, and to be admired in all them that believe (because our testimony among you was believed) in that day.

when he shall come to be glorified in his saints, and to be marvelled at in all them that believed (because our testimony unto you was believed) in that day.

When he shall come to be glorified in his saints, and to be made wonderful in all them who have believed; because our testimony was believed upon you in that day.

when he shall have come to be glorified in his saints, and wondered at in all that have believed, (for our testimony to you has been believed,) in that day.

when he shall come to be glorified in his saints, and to be marveled at in all them that believed (because our testimony unto you was believed) in that day.

when He may come to be glorified in his saints, and to be wondered at in all those believing, because our testimony was believed among you, in that day;

when He comes on that day to be glorified in His people and to be wondered at among all who have believed, including you - because you believed the testimony which we brought for your acceptance.

At his coming, when he will have glory in his saints, and will be a cause of wonder in all those who had faith (because our witness among you had effect) in that day.

when he arrives to be glorified in his saints, and to become a wonder in all those who have believed, in that day, because our testimony has been believed by you.

when he comes to be honored in his people, and to be revered in all who have learned to believe in him (for you also believed our testimony) – as he will be on that day.

When he shall come to be sanctified. As he has hitherto discoursed as to the punishment of the wicked, he now returns to the pious, and says that Christ will come, that he may be glorified in them; that is, that he may irradiate them with his glory, and that they may be partakers of it. "Christ will not have this glory for himself individually; but it will be common to all the saints." This is the crowning and choice consolation of the pious, that when the Son of God will be manifested in the glory of his kingdom, he will gather them into the same fellowship with himself. [1] There is, however, an implied contrast between the present condition in which believers labor and groan, and that final restoration. For they are now exposed to the reproaches of the world, and are looked upon as vile and worthless; but then they will be precious, and full of dignity, when Christ will pour forth his glory upon them. The end of this is, that the pious may as it were, with closed eyes, pursue the brief journey of this earthly life, having their minds always intent upon the future manifestation of Christ's kingdom. For to what purpose does he make mention of His coming in power, but in order that they may in hope leap forward to that blessed resurrection which is as yet hid? It is also to be observed, that after having made use of the term saints, he adds, by way of explanation -- those that believe, by which he intimates that there is no holiness in men without faith, but that all are profane. In the close he again repeats the terms -- in that day, for that expression is connected with this sentence. Now, he repeats it with this view, that he may repress the desires of believers, lest they should hasten forward beyond due bounds. Because credit was given What he had said in a general way as to saints, he now applies to the Thessalonians, that they may not doubt that they are of that number. "Because," says he, "my preaching has obtained credit among you, Christ has already enrolled you in the number of his own people, whom he will make partakers of his glory." He calls his doctrine a testimony, because the Apostles are Christ's witnesses. (Acts 1:8.) Let us learn, therefore, that the promises of God are ratified in us, when they gain credit with us.

Footnotes

1 - "Il les recueillera en plene conionction, et les fera ses consors;" -- "He will gather them in full union, and will make them his partners."

When he shall come to be glorified in his saints - That is, the redeemed in that day will be the means of promoting his glory, or the universe will see his glory manifested in their redemption. His chief glory as seen in that day will be connected with the fact that he has redeemed his people; and he will come in order that all the appropriate honor of such a work may then be manifested. He will be "glorified" then by the numbers that shall have been redeemed; by their patience in the trials through which they have passed; by the triumphs which religion shall have made on the earth; by their praises and songs, and by their ascent with him to the realms of blessedness.
And to be admired in all them that believe - This may either mean that he will be admired among or by them that believe; or that the ground of the admiration which he will receive in that day will be what will be seen in them; that is, their graces, their numbers, their joys, their triumphs will be the occasion of producing admiration of him - for he will be regarded as the source of it all. Tyndale renders it: "and to be made marvelous in all them that believe." The latter interpretation seems to me to be the correct one. The general idea is, that Christ in that day will be manifested in a glorious manner, and that the source of his highest triumphs will be what is seen in the saints. His main honor when he returns to the world will not be the outward splendors which will attend his coming, nor the angels that will accompany him, nor the manifestation of his power over the elements, but the church which he has redeemed. It will then be seen that he is worthy of universal admiration, for having redeemed that church. He shall then be admired or glorified in his people:
(1) for having conceived the plan of redeeming them;
(2) for being willing to become incarnate and to die to save them;
(3) for the defense of his church in all its persecutions and trials;
(4) for raising his people from the dead;
(5) for the virtues and graces which they will exhibit in that day.
This appropriate honor of Christ in the church has never yet been fully seen. His people on earth have, in general, most imperfectly reflected his image. They have in general been comparatively few in number, and scattered upon the earth. They have been poor and despised. Often they have been persecuted and regarded as the "filth of the world and the offscouring of all things." The honors of this world have been withheld from them. The great have regarded it as no honor to be identified with the church, and the proud have been ashamed to be enrolled among the followers of the Lamb. In the last day all this will be changed, and the assembled church will show to admiring worlds how great and glorious is it, Redeemer, and how glorious was the work of redemption.
Because our testimony among you was believed. - The meaning of this seems to be, that they would be among the number of those who would in that day honor the Saviour, because they had embraced what the apostle had preached to them respecting these future scenes. Thus interpreted, this clause should be regarded as connected with 2-Thessalonians 2:7. "And to you it is a righteous thing that he should give rest with us, because our testimony among you was believed," That is, you have shown that you are true Christians, and it is proper that you should partake of the triumphs and hopes of that day.

When he shall come to be glorified in his saints - As the grace of God is peculiarly glorified in saving sinners and making them into saints, this gracious power will be particularly manifested in the great day, when countless millions will appear before that throne who have come out of great tribulation, and have washed their robes and made them white in the blood of the Lamb.
And to be admired - Οαυμασθηναι· To be wondered at among and on the account of all them that believe. Much as true believers admire the perfections of the Redeemer of mankind, and much as they wonder at his amazing condescension in becoming man, and dying for the sins of the world; all their present amazement and wonder will be as nothing when compared with what they shall feel when they come to see him in all his glory, the glory that he had with the father before the world was. In reference to this we may apply those words of St. John: "Beloved, now are we the sons of God; and it doth not yet appear what we shall be: but we know that when he shall appear we shall be like him; for we shall see him as he is." 1-John 3:2.
Instead of τοις πιστευουσιν, them that believe, τοις πιστευσασιν, them that have believed, is the reading of ABCDEF, many others, the later Syriac, Slavonic, Vulgate, and Itala, with most of the Greek fathers. This reading is undoubtedly genuine.
Because our testimony - was believed in that day - The members of this sentence seem to have been strangely transposed. I believe it should be read thus: "In that day, when he shall come to be glorified in his saints, and admired among all them that have believed; for our testimony was believed among you." The Thessalonians had credited what the apostles had said and written, not only concerning Jesus Christ in general, but concerning the day of judgment in particular.

When he shall come to be glorified in his saints, and to be admired in all them that believe ((7) because our testimony among you was believed) in that day.
(7) They are considered as children of God by the faith which they have in the Gospel, which is preached to them by the apostles.

When he shall come to be glorified in his saints,.... Or by them who are set apart for holiness and happiness by God the Father; whose sins are expiated by the blood and sacrifice of Christ; to whom he is made sanctification; and who are sanctified by the Spirit and grace of God; and in whom Christ has a peculiar interest, through his Father's gift, his own purchase, and the power of his grace: and when he comes a second time he will be glorified in these persons; he will appear glorious to them; he will come in his own glory both as God and man; and in his Father's glory, authority, and majesty, conferred on him as the Judge of the whole earth; and with the glory of his angels, who will accompany him. And he will also bestow a glory on them; their souls will be endowed with perfect knowledge and holiness; and their bodies will be made like to his glorious body; and both will shine like the sun in the kingdom of their Father; and this glory on the members of Christ will redound to the glory of him their head. And as he will then, in the most full and clear manner, display the glory of his person and perfections, of his wisdom, power, faithfulness, and goodness, set off the glory of his offices, and, the administration of them, and open the riches both of his grace and glory to them; so they will, in return, ascribe honour, praise, and glory, to him, and give him the glory of their salvation to all eternity:
and to be admired in all them that believe; who are the same with the saints; these are convertible terms; for no man can be a saint, unless he is a believer in Christ, let him make what pretensions to holiness he will: and no man can be a true believer in Christ, unless he is a saint; for true faith works by love, and in a way of holiness; and in those, or by those that are sanctified by faith in him, will he be admired when he appears a second time. He is admired by them now; he is with them the chiefest among ten thousands, and altogether lovely: they wonder at the glory and beauty of his person, and the fulness of his grace; and are amazed that such as they are should be admitted to communion with him; and how much more will they wonder, when they shall see him as he is? and he will be admired by others on the account of them, when they shall see those that they have despised, and persecuted, and accounted as the filth of the world, and the offscouring of all things, received into the arms of Jesus with all the expressions of tenderness and love; placed at his right hand, and set down with him on his throne, clothed with white robes, and crowns on their head, and palms in their hands: and he himself will be admired with them, when they shall see him whom they took to be a mere man, and who was a man of sorrows, and acquainted with griefs, and was loaded with reproach and ignominy, and at last suffered a shameful death, coming in the clouds of heaven in power and great glory as the Judge of quick and dead; thus will he be admired by them, in them, and with them.
(Because our testimony among you was believed) in that day; the phrase, "in that day", belongs to all that goes before, as that Christ shall take vengeance on wicked men, and they shall be punished by him, and he shall be glorified and admired in and by his people in that day, when he shall be revealed from heaven, and come to judge both quick and dead. Though some versions read it in construction with the clause immediately preceding, "because our testimony among you was believed in that day"; or concerning that day; that is, you gave credit to the testimony we bore, when among you, concerning this illustrious day of the Lord; or our testimony, the ministry of the word by us, in which we bore a testimony to the person and grace of Christ, to his first, and to his second coming, was received and embraced by you with a view to this day, and to the enjoyment of the glory of it. The Arabic version renders it, "for our testimony will be true in that day"; that is, it will appear to be so, everything we have said will be accomplished then. The Syriac version is very remote, "that our testimony concerning you may be believed in that day": but it is best to read this clause in a parenthesis, as in our version; which is an application of what is said to the Thessalonians, who might conclude, that since they had embraced the testimony of the Lord Jesus, borne unto him by his apostles, they would be found among the number of the saints and believers, in whom Christ would be glorified and admired; the consideration of which might animate and encourage them to endure afflictions and persecutions with patience, and to hold out to the end, and at last enjoy the heavenly glory, for which the apostle next prays.

"When He shall have come."
glorified in his saints--as the element and mirror IN which His glory shall shine brightly (John 17:10).
admired in all them that believe--Greek, "them that believed." Once they believed, now they see: they had taken His word on trust. Now His word is made good and they need faith no longer. With wonder all celestial intelligences (Ephesians 3:10) shall see and admire the Redeemer on account of the excellencies which He has wrought in them.
because, &c.--Supply for the sense, among whom (namely, those who shall be found to have believed) you, too, shall be; "because our testimony unto (so the Greek for 'among') you was believed" (and was not rejected as by those "who obey not the Gospel," 2-Thessalonians 1:8). The early preaching of the Gospel was not abstract discussions, but a testimony to facts and truths experimentally known (Luke 24:48; Acts 1:8). Faith is defined by BISHOP PEARSON as "an assent unto truths, credible upon the testimony of God, delivered unto us by the apostles and prophets" (originally delivering their testimony orally, but now in their writings). "Glorified in His saints" reminds us that holiness is glory in the bud; glory is holiness manifested.

To be glorified in his saints - For the wonderful glory of Christ shall shine in them.