Genesis 8:21 Updated American Standard Version (UASV)
²¹ Jehovah smelled the soothing aroma; and the Jehovah in his heart, “I will never again curse the ground on account of man, for the intent of man’s heart is evil from his youth;[1] and I will never again destroy every living thing, as I have done.

In 2 Peter 3:10, we are told: “the heavens will pass away with a great noise, and the elements will melt with fervent heat; both the earth and the works that are in it will be burned up.” There are multiple things going on in 2 Peter 2:10, so let us take Genesis 8:21 first. There God was saying that he would never destroy the world in the same way again, in other words, by means of floodwaters. 2 Peter 3:10 is talking about fire, a whole other means.

According to 2 Peter 3:10 in the King James Version, “the earth also and the works that are therein shall be burned up.” However, other modern translations read, “the earth and the works that are done on it will be exposed [or discovered].” This comes about because there is a textual problem, The Codex Sinaiticus and Vatican MS 1209, both of the 4th century C.E., and other manuscripts, read (huerethesetai) “be discovered.” Later manuscripts, the 5th-century Codex Alexandrinus and the 16th-century Clementine recension of the Vulgate, read (katakaesetai) “be burned up.”

Now, looking at the context in 2 Peter, are we talking about the literal earth anyway. Verses 5 and 6 speak of the flood in Noah’s day, likening it to “the day of judgment and destruction of the ungodly” (3:7). First, what was destroyed by the floodwaters? It was not the earth itself that was to be destroyed; it was ungodly men. This is exactly what Peter is talking about as well. The planet earth is not going to be destroyed on judgment day. It will be ungodly men. What is to be “discovered” on the earth in those days after the judgment is righteousness.

Feel regret over: The Hebrew word (נִחוּם nichum or נִחֻם nichum) has the sense of feel regret over. It can be translated as “be sorry,” “grieved,” “repent,” “regret,” “be comforted, “compassion,” “comfort,” “reconsider,” and “change one’s mind.” It can pertain to a change of attitude or intention. God is perfect and therefore does not make mistakes in his dealings with his creation. However, he can have a change of attitude or intention regarding how humans react to his warnings. God can go from the Creator of humans to that of a destroyer of them because of their unrepentant wickedness and failure to heed his warnings. On the other hand, if they repent and turn from their wicked ways, the Father can be compassionate and merciful, slow to anger, and abounding in loyal love. He will “reconsider” the calamity that he may have intended. (Genesis 6:6; Exodus 32:14; Joel 2:13) This is not really God changing his mind per se but rather his altering circumstances once persons with free will brought those altered circumstances about so God could carry out his will and purposes. Second, draw comfort in the fact that we can be sure that God will never change his standards of love and justice regardless of what created beings do with their free will. Nevertheless, just as any of us might change our mind about someone who has altered the way they treat us, God does change in the way that he deals with humans to the evolving circumstances, situations, and conditions. There are also times when God has changed his commands, laws, and instructions according to his people’s situation and needs. We should not be astonished by this because God has foreknowledge, and he is well aware of conditions that will come where he will have to change or alter circumstances. The English word “regret” means ‘to feel sorry and sad about something previously done or said that now appears wrong, mistaken, or hurtful to others.’ The Hebrew word (nacham here translated as “regretted” relates to a change of attitude or intention. The Hebrew could not be used to suggest that God felt that he had made a mistake in creating man. – See Malachi 3:6 as well.

[1] American Translation: “the bent of man’s mind may be evil from his very youth.” In other words, all imperfect humans are mentally bent toward evil.