Thank you for the question on the character of God, “How come God repented (Exodus 32:14 KJV) if he doesn’t repent (Numbers 23:19 KJV)?”
As one reads any literature, including the Scriptures, the meaning of a word and the context will aid in understanding a particular word choice.
The KJV uses the term, repented while the NIV uses the term, relented. There is the lexicon definition of repent is generally understood as a change of mind or changing a course of action.
The Hebrew word most often translated as repentance is “teshuva”. The root word is shuv, which means “turning back.” The first used is in Genesis 3:19 whereby God declares to Adam that he will turn back to dirt from which he was made from.
In Exodus 32:14, God had already given the Ten Commandments whereby the people agreed to worship the Creator God, YHWH. The Israelites engaged in idolatry and wonton living in the absence of Moses. God reveals his intention to Moses of destroying the people and raising a new generation through him.
Exodus 32:9–10 expresses God’s intention. The KJV says this, “And the Lord said unto Moses, I have seen this people, and, behold, it is a stiffnecked people: 10 Now therefore let me alone, that my wrath may wax hot against them, and that I may consume them: and I will make of thee a great nation.”
Note carefully that God did not say that he WILL but MAY. The word, may, suggests a real possible action by God, but it is not determined action. If no one interviewed for the Israelites, God may allow his anger to rise to a level that he will consume/destroy them. Thus God didn’t change his mind. He didn’t determined to destroy them and then changed his mind. He expressed an option of his action and Moses pleaded for the mercy of God to forego that option of destroying the Israrelites..
In Numbers 23:19, it is Balaam speaking about his experience with God. What God has revealed to him, that he will do. Balaam couldn’t change the mind of God. God had determine that his people will be blessed and that they will enter the Promised God. Balaam knew that God was not going to change his mind on that point. Balaam affirms that to Balak, “Did I not tell you I must do whatever the LORD says” (vs. 26).
Balaam’s observation of the character of God is that God is not a man that he should lie, nor a son of man, that he should change his mind. Balaam knew that God was not going to repent of his determination to bless them and to change it to cursing them because Balak’s requested it. What Balak wanted contradicted God’s determined purpose. It is Balak who hoped that God will changed his mind, not that God was going to change his mind.
Humans may rescind or violate their words because on perceived advantage for them. It is human who says one thing and then do something else. What God has declared, he has obligated himself to fulfill it.
SUMMARY: Exodus 32:13 express God’s option by using the word, may, while in Numbers 23:19 expresses Balaam’s perceived determined will of God to bless his people in conquering and inheriting the Promised Land. God didn’t repent/change his mind from blessing his people to cursing his people.
For more perspectives:
https://www.quora.com/How-come-God-repented-Exodus-32-14-KJV-if-he-doesnt-repent-Numbers-23-19-KJV