There is a final lesson from the book of Jonah, one that is important for every believer. God never asks us to do anything that he is not prepared to do himself. He never asks us to be irresponsible, or to have bad judgment, or to perform any sinful act. What God asks of us is repentance. In our case, repentance involves sorrow over our offense to God and to turn away from acts of sin and walk according to God's plan. So what does it mean in Jonah 3.10 when it states that God "relented", or as some translations put it, "repented"?

Since there is no sin in God, his sorrow is isn't over sin as ours is. Instead, God's sorrow is regarding justice. This may seem counter-intuitive, since justice is not sin. Had the people of Nineveh not turned from evil they would have experienced God's justice, but due to their response they experienced God's mercy. The penitent are always spared God's justice. The mechanism for this change, from justice to mercy, involved two parts: the people's change of heart and God's turning around and walking in the opposite direction — not away from them as justice demands but toward them as mercy desires.

What makes this verse so difficult to translate is the underlying Hebrew. The word translated "repent" regarding the people's response to God's judgment is in fact different from the word used for God's response. Several Hebrew words have overlapping definitions, but the author specifically chose these two words to indicate a difference. Most modern scholars believe "relent" is the proper rendering. For this reason, the NET translation doesn't use the word "repent" in this passage even though that is the most literal rendering: "When God saw their actions – they turned from their evil way of living! – God relented concerning the judgment he had threatened them with and he did not destroy them." In this case, the translators chose the phrase "turned from their evil way" to describe the people's actions and the word "relent", which means "to soften or become forgiving," for God's response. This works, as far as it goes. It's weakness is that it doesn't have the same force as repentance; its strength is that it doesn't lead one to believe that God may have made a mistake — or worse, that God had sinned.

This is a case where, when developing good Biblical theology, we must allow our understanding of a passage to be guided by previously established theology. We know that God does not change (James 1.17, Malachi 1.17). This is called the Immutability of God. "This does not mean that [God] is immobile or inactive, but it does mean that he is never inconsistent or growing or developing" (Charles Ryrie, Basic Theology, Victor Books, ©1977). Because God cannot change he cannot become something that he wasn't before. For this reason we know that God cannot sin or make a mistake or error in judgment (1 Peter 2.22). God is perfect in all his ways, even when he relents so that mercy may triumph over justice.

This truth raises an interesting question: if God is immutable then what did Paul mean when he wrote, "God made the one who did not know sin to be sin for us, so that in him we would become the righteousness of God" (2 Corinthians 5.21)? The best answer to this question comes from another prophet, Isaiah:

But he lifted up our illnesses,

he carried our pain;

even though we thought he was being punished,

attacked by God, and afflicted for something he had done.

He was wounded because of our rebellious deeds,

crushed because of our sins;

he endured punishment that made us well;

because of his wounds we have been healed...

Though the Lord desired to crush him and make him ill,

once restitution is made,

he will see descendants and enjoy long life,

and the Lord’s purpose will be accomplished through him.

Jesus did not literally become sin, for it is impossible for sin to become personified, but rather he took upon himself all the wrath of God that would have been poured out on all humanity due to their sin. In this way, God did not need to repent or relent and yet mercy may still triumph over justice. The end result is not that God changed, but that we change and become the righteousness of God.