But, beloved, be not ignorant of this one thing, that one day is with the Lord as a thousand years, and a thousand years as one day.

But of this one thing be not ignorant, my beloved, that one day with the Lord is as a thousand years, and a thousand years as one day.

But let not this one thing be hidden from you, beloved, that one day with the Lord is as a thousand years, and a thousand years as one day.

And this one thing let not be unobserved by you, beloved, that one day with the Lord is as a thousand years, and a thousand years as one day;

But there is one thing, dear friends, which you must not forget. With the Lord one day resembles a thousand years and a thousand years resemble one day.

But, my loved ones, keep in mind this one thing, that with the Lord one day is the same as a thousand years, and a thousand years are no more than one day.

Yet truly, let this one thing not escape notice, most beloved, that with the Lord one day is like a thousand years, and a thousand years is like one day.

But you, dear friends, must never shut your eyes to the fact that, to the Lord, one day is the same as a thousand years, and a thousand years as one day.

But be not ignorant of this one thing. He now turns to speak to the godly; and he reminds them that when the coming of Christ is the subject, they were to raise upwards their eyes, for by so doing, they would not limit, by their unreasonable wishes, the time appointed by the Lord. For waiting seems very long on this account, because we have our eyes fixed on the shortness of the present life, and we also increase weariness by computing days, hours, and minutes. But when the eternity of God's kingdom comes to our minds, many ages vanish away like so many moments. This then is what the Apostle calls our attention to, so that we may know that the day of resurrection does not depend on the present flow of time, but on the hidden purpose of God, as though he had said, "Men wish to anticipate God for this reason, because they measure time according to the judgment of their own flesh; and they are by nature inclined to impatience, so that celerity is even delay to them: do ye then ascend in your minds to heaven, and thus time will be to you neither long nor short."

But, beloved, be not ignorant of this one thing, that one day is with the Lord as a thousand years - This 2-Peter 3:8-9 is the second consideration by which the apostle meets the objection of scoffers against the doctrine of the second coming of the Saviour. The objection was, that much time, and perhaps the time which had been supposed to be set for his coming, had passed away, and still all things remained as they were. The reply of the apostle is, that no argument could be drawn from this, for that which may seem to be a long time to us is a brief period with God. In the infinity of his own duration there is abundant time to accomplish his designs, and it can make no difference with him whether they are accomplished in one day or extended to one thousand years. Man has but a short time to live, and if he does not accomplish his purposes in a very brief period, he never will. But it is not so with God. He always lives; and we cannot therefore infer, because the execution of His purposes seems to be delayed, that they are abandoned. With Him who always lives it will be as easy to accomplish them at a far distant period as now. If it is His pleasure to accomplish them in a single day, He can do it; if He chooses that the execution shall be deferred to one thousand years, or that one thousand years shall be consumed in executing them, He has power to carry them onward through what seems, to us, to be so vast a duration. The wicked, therefore, cannot infer that they will escape because their punishment is delayed; nor should the righteous fear that the divine promises will fail because ages pass away before they are accomplished. The expression here used, that "one day is with the Lord as a thousand years, etc.," is common in the Rabbinical writings. See Wetstein in loc. A similar thought occurs in Psalm 90:4; "For a thousand years in thy sight are but as yesterday when it is past, and as a watch in the night."

Be not ignorant - Though they are wilfully ignorant, neglect not ye the means of instruction.
One day is with the Lord as a thousand years - That is: All time is as nothing before him, because in the presence as in the nature of God all is eternity; therefore nothing is long, nothing short, before him; no lapse of ages impairs his purposes, nor need he wait to find convenience to execute those purposes. And when the longest period of time has passed by, it is but as a moment or indivisible point in comparison of eternity. This thought is well expressed by Plutarch, Consol. ad Apoll.: "If we compare the time of life with eternity, we shall find no difference between long and short. Τα γαρ χιλια, και τα μυρια ετη, στιγμη τις εστιν αοριστος, μαλλον δε μοριον τι βραχυτατον στιγμης· for a thousand or ten thousand years are but a certain indefinite point, or rather the smallest part of a point." The words of the apostle seem to be a quotation from Psalm 90:4.

(7) But, beloved, be not ignorant of this one thing, that one day [is] with the Lord as a thousand years, and a thousand years as one day.
(7) The taking away of an objection: in that he seems to desire this judgment for a long time, in respect of us it is true, but not before God, which whom there is no time either long or short.

But, beloved, be not ignorant of this one thing,.... Here the apostle addresses the saints he writes unto, and for whom he had a tender affection and regard, and for whose welfare he was concerned, lest they should be stumbled at the length of time since the promise of the coming of Christ was given, and which these scoffers object; and therefore he would have them know, observe, and consider this one thing, which might be of great use to them to make their minds easy, and keep up their faith and expectation of the coming of Christ:
that one day is, with the Lord as a thousand years, and a thousand years as one day; referring either to Psalm 90:4; or to a common saying among the Jews, founded on the same passage, , "the day of the holy blessed God is a thousand years" (z); suggesting, that though between thirty and forty years had elapsed since the promise was given out that Christ would come again, and should even a thousand, or two thousand years more, run off, before the coming of Christ, yet this should be no objection to the accomplishment of the promise; for though such a number of years is very considerable among men, ye not "with God", as the Arabic and Ethiopic versions read, with whom a thousand years, and even eternity itself, is but as a day, Isaiah 43:13. Unless this phrase should be thought to refer, as it is by some, to the day of judgment, and be expressive of the duration of that: it is certain that the Jews interpreted days of millenniums, and reckoned millenniums by days, and used this phrase in confirmation of it. Thus they say (a),
"in the time to come, which is in the last days, on the sixth day, which is the sixth millennium, when the Messiah comes, for the day of the holy blessed God is a thousand years.''
And a little after,
""the Lord hath created a new thing in the earth, a woman shall compass a man". This is in the time of the Messiah which is in the sixth day.''
And elsewhere (b),
"the sixth degree is called the sixth day, the day of the holy blessed God is a thousand years. And in that day the King Messiah shall come, and it shall be called the feast of gathering, for the holy blessed God will gather in it the captivity of his people.''
So they call the sabbath, or seventh day, the seventh millennium, and interpret (c).
""the song for the sabbath day", Psalm 92:1 title, for the seventh millennium, for one day of the holy blessed God is a thousand years.''
To which agrees the tradition of Elias, which runs thus (d);
"it is the tradition of the house of Elias, that the world shall be six thousand years, two thousand years void (of the law), two thousand years the law, and two thousand years the days of the Messiah;''
for they suppose that the six days of the creation were expressive of the six thousand years in which the world will stand; and that the seventh day prefigures the last millennium, in which will be the day of judgment, and the world to come; for
"the six days of the creation (they say (e)) is a sign or intimation of these things: on the sixth day man was created; and on the seventh his work was finished; so the kings of the nations of the world (continue) five millenniums, answering to the five days, in which were created the fowls, and the creeping things of the waters, and other things; and the enjoyment of their kingdom is a little in the sixth, answerable to the creation of the beasts, and living creatures created at this time in the beginning of it; and the kingdom of the house of David is in the sixth millennium, answerable to the creation of man, who knew his Creator, and ruled over them all; and in the end of that millennium will be the day of judgment, answerable to man, who was judged in the end of it; and the seventh is the sabbath, and it is the beginning of the world to come.''
(z) Bereshit Rabba, sect. 8. fol. 7. 3. Vajikra Rabba, sect. 19. fol. 160. 2. Bemidbar Rabba, sect. 14. fol. 216. 1. Shirhashirim Rabba, fol. 20. 1. Zohar in Exod. fol. 60. 1. Tzeror Hammor, fol. 157. 1. & Nishmet Chayim Orat. 1. c. 5. fol. 12. 1. (a) Zohar in Genesis. fol. 13. 4. (b) Ib. fol. 16. 1. (c) Bartenora in Misn. Tamid, c. 7. sect. 4. (d) T. Bab. Sanhedrin, fol. 97. 1. & Avoda Zara, fol. 9. 1. (e) Ceseph Misna in Maimon. Hilchot Teshuva, c. 9. sect. 2.

be not ignorant--as those scoffers are (2-Peter 3:5). Besides the refutation of them (2-Peter 3:5-7) drawn from the history of the deluge, here he adds another (addressed more to believers than to the mockers): God's delay in fulfilling His promise is not, like men's delays, owing to inability or fickleness in keeping His word, but through "long-suffering."
this one thing--as the consideration of chief importance (Luke 10:42).
one day . . . thousand years-- (Psalm 90:4): Moses there says, Thy eternity, knowing no distinction between a thousand years and a day, is the refuge of us creatures of a day. Peter views God's eternity in relation to the last day: that day seems to us, short-lived beings, long in coming, but with the Lord the interval is irrespective of the idea of long or short. His eternity exceeds all measures of time: to His divine knowledge all future things are present: His power requires not long delays for the performance of His work: His long-suffering excludes all impatient expectation and eager haste, such as we men feel. He is equally blessed in one day and in a thousand years. He can do the work of a thousand years in one day: so in 2-Peter 3:9 it is said, "He is not slack," that is, "slow": He has always the power to fulfil His "promise."
thousand years as one day--No delay which occurs is long to God: as to a man of countless riches, a thousand guineas are as a single penny. God's œonologe (eternal-ages measurer) differs wholly from man's horologe (hour-glass). His gnomon (dial-pointer) shows all the hours at once in the greatest activity and in perfect repose. To Him the hours pass away, neither more slowly, nor more quickly, than befits His economy. There is nothing to make Him need either to hasten or delay the end. The words, "with the Lord" (Psalm 90:4, "In Thy sight"), silence all man's objections on the ground of his incapability of understanding this [BENGEL].

But, beloved, be not ignorant. Delay was the objection of the scoffers, but time is no element in the counsels of God. He has eternity in which to work out his purposes. He can as well take a thousand years as a day. If he seems to us short lived creatures to delay it for wise purposes. See Psalm 90:4.
The Lord is not slack. If the day of the Lord seems delayed it is not due to slackness. It is rather because God is long suffering and is giving time to call the world to repentance. See 1-Timothy 2:4.
But the day of the Lord will come. This expression usually, but not always, refers to the second advent. Such is the meaning here.
As a thief. When people are not expecting it. Compare 1-Thessalonians 5:2; Matthew 24:43.
The heavens shall pass away. See Luke 21:33.
The elements shall melt. The material of which they are composed.
The earth also and the works. The earth and all man's creations. That the world shall come to an end seems to be written in its very constitution. A slight change in the constitution of the atmosphere, or the decomposition of its water would wrap it in flame. Science finds the elements of final dissolution in the relations of the earth and sun. According to the ratio of increase in two centuries the world will not have resources to feed its population. In a few hundred years the coal resources of the world will fail. These and many other facts point to a necessary and inevitable change.
What manner of persons ought ye to be. Since we have no abiding home on this earth and seek one beyond, we should live in a state of preparation.
Looking for. Looking for, preparing for, and desiring the Lord's coming. Dreadful as that day will be for the impenitent it is a day of relief and of glorious attainment to the saint.
We, according to his promise. See Isaiah 65:17; also Isaiah 66:22. The heavens and the earth are not to be blotted out, but changed, purified, and made better for the home of the righteous.

But be not ye ignorant - Whatever they are. Of this one thing - Which casts much light on the point in hand. That one day is with the Lord as a thousand years, and a thousand years as one day - Moses had said, Psalm 90:4, "A thousand years in thy sight are as one day;" which St. Peter applies with regard to the last day, so as to denote both his eternity, whereby he exceeds all measure of time in his essence and in his operation; his knowledge, to which all things past or to come are present every moment; his power, which needs no long delay, in order to bring its work to perfection; and his longsuffering, which excludes all impatience of expectation, and desire of making haste. One day is with the Lord as a thousand years - That is, in one day, in one moment he can do the work of a thousand years. Therefore he "is not slow:" he is always equally ready to fulfil his promise. And a thousand years are as one day - That is, no delay is long to God. A thousand years are as one day to the eternal God. Therefore "he is longsuffering:" he gives us space for repentance, without any inconvenience to himself. In a word, with God time passes neither slower nor swifter than is suitable to him and his economy; nor can there be any reason why it should be necessary for him either to delay or hasten the end of all things. How can we comprehend this? If we could comprehend it, St. Peter needed not to have added, with the Lord.