And the LORD smelled a {k} sweet savour; and the LORD said in his heart, I will not again curse the ground any more for man's sake; for the imagination of man's heart is evil from his youth; neither will I again smite any more every thing living, as I have done.

(k) That is, by it he showed himself appeased and his anger at rest.

Wesley's Notes

8:21 And God smelled a sweet savour - Or a savour of rest from it, as it is in the Hebrew. He was well pleased with Noah's pious zeal, and these hopeful beginnings of the new world, as men are with fragrant and agreeable smells. I will not again curse the ground, Heb. I will not add to curse the ground any more - God had cursed the ground upon the first entrance of sin, Ge 3:17, when he drowned it he added to that curse: but now he determines not to add to it any more. Neither will I again smite any more every living thing - That is, it was determined that whatever ruin God might bring upon particular persons, families or countries, he would never again destroy the whole world, 'till the day when time shall be no more. But the reason of this resolve is surprising; for it seems the same with the reason given for the destruction of the world, Ge 6:5. Because the imagination of man's heart is evil from his youth. But there is this difference: there it is said, the imagination of man's heart is evil continually, that is, his actual transgressions continually cry against him; here it is said, that it is evil from his youth or childhood; he brought it into the world with him, he was shapen and conceived in it. Now one would think it should follow, therefore that guilty race shall be wholly extinguished: No; therefore I will no more take this severe method; for he is rather to be pitied: and it is but what might be expected from such a degenerate race. So that if he be dealt with according to his deserts, one flood must succeed another 'till all be destroyed. God also promises, that the course of nature should never be discontinued. While the earth remaineth, and man upon it, there shall be summer and winter, not all winter, as had been this last year; day and night, not all night, as probably it was while the rain was descending. Here it is plainly intimated that this earth is not to remain always; it and all the works therein must shortly be burnt up. But as long as it doth remain, God's providence will carefully preserve the regular succession of times and seasons. To this we owe it, that the world stands, and the wheel of nature keeps its tack. See here how changeable the times are, and yet how unchangeable!
1. The course of nature always changing. As it is with the times, so it is with the events of time, they are subject to vicissitudes, day and night, summer and winter counterchanged. In heaven and hell it is not so; but on earth God hath set the one over against the other.
2. Yet never changed; it is constant in this inconstancy; these seasons have never ceased, nor shall cease while the sun continues such a steady measurer of time, and the moon such a faithful witness in heaven. This is God's covenant of the day and of the night, the stability of which is mentioned for the confirming our faith in the covenant of grace, which is no less inviolable, Jer 33:20. We see God's promises to the creatures made good, and thence may infer that his promises to believers shall be so.

King James Translators' Notes

a sweet...: Heb. a savour of rest or, satisfaction

for the imagination: or, through the imagination

Scofield Reference Notes

[1] the Lord said in heart

The Third Dispensation: Human Government. Under Conscience, as in Innocency, man utterly failed, and the judgment of the Flood marks the end of the second dispensation and the beginning of the third. The declaration of the Noahic Covenant subjects humanity to a new test. Its distinctive feature is the institution, for the first time, of human government--the government of man by man. The highest function of government is the judicial taking of life. All other governmental powers are implied in that. It follows that the third dispensation is distinctively that of human government. Man is responsible to govern the world for God. That responsibility rested upon the whole race, Jew and Gentile, until the failure of Israel under the Palestinian Covenant (Deu 28.-30.1-10) brought the judgment of the Captivities, when "the times of the Gentiles" (See) Lk 21:24 Rev 16:14 began, and the government of the world passed exclusively into Gentile hands Dan 2:36-45 Lk 21:24 Acts 15:14-17. That both Israel and the Gentiles have governed for self, not God, is sadly apparent. The judgment of the confusion of tongues ended the racial testing; that of the captivities the Jewish; while the Gentile testing will end in the smiting of the Image (Da 2.) and the judgment of the nations Mt 25:31-46. See, for the other six dispensations:

INNOCENCE See Scofield Note: "Gen 1:28"

CONSCIENCE See Scofield Note: "Gen 3:23"

PROMISE See Scofield Note: "Gen 12:1"

LAW See Scofield Note: "Ex 19:8"

GRACE See Scofield Note: "Jn 1:17"

KINGDOM See Scofield Note: "Eph 1:10"

Jamieson-Fausset-Brown Bible Commentary

21. And the Lord smelled a sweet savour-The sacrifice offered by a righteous man like Noah in faith was acceptable as the most fragrant incense.

Lord said in his heart-same as "I have sworn that the waters of Noah should no more go over the earth" (Isa 54:9).

for-that is, "though the imagination is evil"; instead of inflicting another destructive flood, I shall spare them-to enjoy the blessings of grace, through a Saviour.

Matthew Henry's Concise Commentary

8:20-22 Noah was now gone out into a desolate world, where, one might have thought, his first care would have been to build a house for himself, but he begins with an alter for God. He begins well, that begins with God. Though Noah's stock of cattle was small, and that saved at great care and pains, yet he did not grudge to serve God out of it. Serving God with our little is the way to make it more; we must never think that is wasted with which God is honoured. The first thing done in the new world was an act of worship. We are now to express our thankfulness, not by burnt-offerings, but by praise, and pious devotions and conversation. God was well pleased with what was done. But the burning flesh could no more please God, than the blood of bulls and goats, except as typical of the sacrifice of Christ, and expressing Noah's humble faith and devotedness to God. The flood washed away the race of wicked men, but it did not remove sin from man's nature, who being conceived and born in sin, thinks, devises, and loves wickedness, even from his youth, and that as much since the flood as before. But God graciously declared he never would drown the world again. While the earth remains, and man upon it, there shall be summer and winter. It is plain that this earth is not to remain always. It, and all the works in it, must shortly be burned up; and we look for new heavens and a new earth, when all these things shall be dissolved. But as long as it does remain, God's providence will cause the course of times and seasons to go on, and makes each to know its place. And on this word we depend, that thus it shall be. We see God's promises to the creatures made good, and may infer that his promises to all believers shall be so.