But if it be of God, ye cannot overthrow it; lest haply ye be found even to fight against God.

but if it is of God, ye will not be able to overthrow them; lest haply ye be found even to be fighting against God.

But if it be of God, you cannot overthrow it, lest perhaps you be found even to fight against God. And they consented to him.

but if it be from God, ye will not be able to put them down, lest ye be found also fighters against God.

and if it be of God, ye are not able to overthrow it, lest perhaps also ye be found fighting against God.'

But if it is really from God, you will be powerless to put them down - lest perhaps you find yourselves to be actually fighting against God."

But if it is of God, you will not be able to overcome them, and you are in danger of fighting against God.

Yet truly, if it is of God, you will not be able to break it, and perhaps you might be found to have fought against God." And they agreed with him.

but, if they are of divine origin, you will be powerless to put an end to them – or else you may find yourselves fighting against God!"

But if it be of God - If God is the "author" of this religion. From this it seems that Gamaliel supposed that it was at least possible that this religion was divine. He evinced a far more candid mind than did the rest of the Jews; but still it does not appear that he was entirely convinced. The arguments which could not but stagger the Jewish Sanhedrin were those drawn from the resurrection of Jesus, the miracle on the day of Pentecost, the healing of the lame man in the temple, and the release of the apostles from the prison.
Ye cannot overthrow it - Because:
(1) God has almighty power, and can execute his purposes;
(2) Because he is unchanging, and will not be diverted from his plans, Job 23:13-14.
The plan which God forms "must" be accomplished. All the devices of man are feebleness when opposed to him, and he can dash them in pieces in an instant. The prediction of Gamaliel has been fulfilled. People have opposed Christianity in every way, but in vain. They have reviled it; have persecuted it; have resorted to argument and to ridicule; to fire, and faggot, and sword; they have called in the aid of science; but all has been in vain. The more it has been crushed, the more it has risen, and it still exists with as much life and power as ever. The "preservation" of this religion amidst so much and so varied opposition proves that it is of God. No severer trial "can" await it than it has already experienced; and as it has survived so many storms and trials, we have every evidence that, according to the predictions, it is destined to live and to fill the world. See the Matthew 16:18; Isaiah 54:17; Isaiah 55:11 notes; Daniel 4:35 note.
Lest - That is, if you continue to oppose it, you may be found to have been opposing God.
Haply - Perhaps. In the Greek this is "lest at any time"; that is, at some future time, when too late to retract your doings, etc.
Ye be found - It shall appear that you have been opposing God.
Even to fight against God - Greek Θεομάχοι Theomachoi, "those who contend with God." The word occurs nowhere else in the New Testament. To fight against God is to oppose him, or to maintain an attitude of hostility against him. It is an attitude that is most fearful in its character, and will most certainly be attended with an overthrow. No condition can be more awful than such an opposition to the Almighty; no overthrow more terrible than what must follow such opposition. Compare Acts 9:5; Acts 23:9. Opposition to the "gospel" in the Scriptures is uniformly regarded as opposition to God, Matthew 12:30; Luke 11:23. People may be said to "fight against" God in the following ways, or on the following subjects:
(1) When they oppose his "gospel," its preaching, its plans, its influence among people; when they endeavor to prevent its diffusion, or to withdraw their families and friends from its influence.
(2) when they oppose the "doctrines" of the Bible. When they become angry that the real truths of religion are preached, and suffer themselves to be irritated and excited by an "unwillingness" that those doctrines should be true, and should be presented to people. Yet this is no uncommon thing. People by nature do not love those doctrines, and they are often indignant that they are preached. Some of the most angry feelings which people ever have arise from this source; and man can never find peace until he is "willing" that God's truth should exert its influence on his own soul, and rejoice that it is believed and loved by others.
(3) people oppose the "Law" of God. It seems to them too "stern" and "harsh." It condemns them; and they are unwilling that it should be applied to them. There is nothing which a sinner likes "less" than he does the pure and holy Law of God.
(4) sinners fight against the "providence" of God. When he afflicts them they rebel. When he takes away their health, or property, or friends, they complain. They esteem him harsh and cruel; and instead of finding peace by "submission," they greatly aggravate their sufferings, and infuse a mixture of wormwood and gall into the cup by complaining and repining. There is no peace in affliction but in the feeling that God is "right." And until this belief is cherished, the wicked will be like the troubled sea which cannot rest, whose waters cast up mire and dirt, Isaiah 57:20. Such opposition to God is as wicked as it is foolish. The Lord gave, and has a right to remove our comforts; and we should be still, and know that he is God.
(5) sinners fight against God when they resist the influences of his Spirit; when they "oppose" serious thoughts; when they seek evil or frivolous companions and pleasures rather than submit to God; and when they spurn all the entreaties of their friends to become Christians. All these may be the appeals which God is making to people to be prepared to meet him. And yet it is common for sinners thus to stifle conviction, and refuse even to think of their eternal welfare. Nothing can be an act of more direct and deliberate wickedness and folly than this. Without the aid of the Holy Spirit none can be saved; and to resist his influences is to put away the only prospect of eternal life. To do it is to do it over the grave; not knowing that another hour of life may be granted; and not knowing that "if" life is prolonged, the Spirit will ever strive again with the heart. In view of this verse, we may remark:
1. That the path of wisdom is to submit at once to the requirements of God. Without this, we must expect conflicts with him, and peril and ruin. No man can be "opposed" to God without endangering himself every minute.
2. Submission to God should be entire. It should extend to every doctrine and demand; every law, and every act of the Almighty. In all his requirements, and in all afflictions, we should submit to him, for thus only shall we find peace.
3. Infidels and scoffers will gain nothing by opposing God. They have thus far been thwarted, and unsuccessful; and they will be still. None of their plans have succeeded; and the hope of destroying the Christian religion, after the efforts of almost two thousand years, must be vain, and will recoil with tremendous vengeance on those who make them.

But if it be of God, ye cannot overthrow it - Because his counsel cannot fail; and his work cannot be counteracted. If he be determined that this doctrine shall prevail, it is vain for us to attempt to suppress it.
Lest haply ye be found - to fight against God - Μηποτε και θεομαχοι εὑρεθητε. Some have thought that they saw a parallel to these words in the speech of Diomede, when, seeing Mars, associated with Hector, oppose the Grecians, he judged farther opposition vain, and desired his troops to retire from the battle.
Τῳ δ' αιει παρα εἱς γε θεων, ὁς λοιγον αμυνει·
Και νυν οἱ παρα κεινος Αρης, βροτῳ ανδρι εοικως.
Αλλα προς Τρωας τετραμμενοι αιεν οπισσω
Εικετε, μηδε Θεοις μενεαινεμεν ιφι μαχεσθαι.
Iliad, lib. v. 603.
Protected always by some power divine;
And Mars attends this moment at his side,
In form a man. Ye therefore still retire,
But facing still your foes: nor battle wage,
However fierce, yet fruitless, with the gods.
Cowper.

But if it be of God,.... If it is according to the counsel of his will; if it is a scheme of his forming, and a work to which he has called these men, and they proceed in it on good principles, and with a view to the honour and glory of God:
ye cannot overthrow it; it will proceed and get ground, and stand, maugre all the opposition of hell and earth; therefore do nothing to them, or hinder them from going on. Some copies read, "ye cannot overthrow them"; and add, "neither you, nor kings, nor tyrants; wherefore refrain from these men"; so Beza's Cambridge copy.
Lest haply ye be found even to fight against God; which to do is downright madness, and which no man in his senses can expect to succeed in. There are some sayings of the Jewish doctors which seem to agree with these reasonings of Gamaliel (p).
"Says R. Jochanan the shoemaker, every congregation, which is for the name of heaven (or God) at length shall be established, but that which is not for the glory of God shall not be established in the end.''
Which one of the commentators (q) interprets in words still nearer to Gamaliel's language, thus:
"it shall be that that counsel which is for God shall stand and prosper, but that which is not for God shall cease.''
And in another place it is said (r),
"all contention (or dispute) which is for God, at length shall be established, but that which is not for God shall not in the end be established: what is contention that is for God? the contention of Hillell and Shammai, (two famous doctors among the Jews,) but that which is not for God is the contention of Korah, and his whole company.''
Some have thought from this advice of Gamaliel, that he was a Christian, or greatly inclined to Christianity; but when it is considered what respect was shown him at his death by the Jews, before observed on Acts 5:34 it will appear that he died a Pharisee; and especially it cannot be thought he had any favourable sentiments of the Christians, since a little before his death he ordered a prayer to be made against them. Maimonides says (s), that
"in the days of Rabban Gamaliel, the Epicureans (so the Amsterdam edition reads, but former editions read "heretics", by whom are meant Christians) increased in Israel; and they distressed the Israelites, and seduced them to turn aside from God; and when he saw that this was greater than all the necessities of the children of men, he stood up, and his council or sanhedrim, and composed another prayer, in which there was a request to God to destroy the Epicureans,''
or heretics, meaning the Christians: and though this prayer is sometimes ascribed to Samuel the little, yet it was composed by him at the hint and instigation of Gamaliel; for so it is said (t), R. Gamaliel said to the wise men,
"is there no man that knows how to compose a prayer for the Sadducees? (R. Asher reads "heretics";) Samuel the little stood up and composed one.''
And it is also said (u), that
"Samuel the little composed, , "the prayer for the heretics", before, or in the presence of Gamaliel the elder.''
He made it when he was present, assisting, dictating, directing, and approving. The prayer was this (w),
"let there be no hope for apostates, and may all heretics perish in a moment, and all the enemies of thy people be quickly cut off: root out the kingdom of pride, and break, destroy, and subdue them in haste in our days.''
In some forms it is added,
"blessed art thou, O Lord, that breakest the wicked in pieces, and humblest the proud.''
Upon the whole, Gamaliel does not seem to have been a Christian, or to have favoured the Christian religion; but he was, as he is said, Acts 5:34 to be, a Pharisee: and this council, or sanhedrim, were, for the greater part of them, Sadducees, as seems from Acts 5:17 who, as the Jews say, were wicked and base men, men of very ill manners, whereas the Pharisees were "merciful men" (x); and such an one was Gamaliel: he was a religious man in his way; a man of humanity, a mild and moderate man, that had compassion and pity for his fellow creatures; and could not give in to any schemes of cruelty and persecution, which the Sadducees were forward to; and upon these principles he acted, and upon these he gave this advice.
(p) Pirke Abot, c. 4 sect 11. (q) Jarchi in ib. (r) Pirke Abot, c. 5. sect. 17. (s) Hilchot Tephilla, c. 2. sect. 1. (t) T. Bab. Beracot, fol. 28. 2. (u) Juchasin, fol. 21. 1. Ganz Tzemach David, par. 1. fol. 25. 2. (w) Apud Buxtorf. Lex. Talmud. col. 2442. & Alting Shilo, l. 4. c. 26. p. 325. (x) Juchasin, fol. 139. 1.