What made God finally forgive the children of Israel?

Answer 1

Christian answer:

God's forgiveness of the children of Israel is still pending, dependent upon their recognition of Jesus as the Messiah.

Matthew 23:37-39 - "O Jerusalem, Jerusalem, the one who kills the prophets and stones those who are sent to her! How often I wanted to gather your children together, as a hen gathers her chicks under her wings, but you were not willing! See! Your house is left to you desolate; for I say to you, you shall see Me no more till you say, 'Blessed is He who comes in the name of the LORD."

Romans 9:30-33 - What shall we say then? That Gentiles, who did not pursue righteousness, have attained to righteousness, even the righteousness of faith; but Israel, pursuing the law of righteousness, has not attained to the law of righteousness. Why? Because they did not seek it by faith, but as it were, by the works of the law. For they stumbled at that stumbling stone. As it is written: "Behold, I lay in Zion a stumbling stone and rock of offense, And whoever believes on Him will not be put to shame." [NKJV]

That it WILL happen some day is certain; first, because God has promised them healing and forgiveness, and second, because Jesus said (in Matthew 23:39, above), "till you say...", not "unless you say" or "if you say." This amounts to a prophecy by Jesus that the Jews shall one day express faith in Him as their Messiah and the Savior of all men, thus meeting God's terms of forgiveness.

Jewish Answer:

God's power to forgive is infinite.

Answer 2

That depends which event you're asking about. In any case, the following links may be useful. The complaints in the wilderness and the Golden Calf

Why the Prophets scolded the Israelites