Moses' prayer for Israel's forgiveness is found in Exodus 32:11-14. The incident takes place when Moses is on Mount Sinai receiving the Ten Commandments from God. While he is away, the Israelites grow impatient and ask Aaron to make them a golden calf to worship as a god.

When God sees what the Israelites are doing, he becomes angry and threatens to destroy them. However, Moses intercedes on behalf of the people and pleads for God's mercy and forgiveness:

"But Moses implored the Lord his God and said, 'O Lord, why does your wrath burn hot against your people, whom you have brought out of the land of Egypt with great power and with a mighty hand? Why should the Egyptians say, "With evil intent did he bring them out, to kill them in the mountains and to consume them from the face of the earth"? Turn from your burning anger and relent from this disaster against your people. Remember Abraham, Isaac, and Israel, your servants, to whom you swore by your own self, and said to them, "I will multiply your offspring as the stars of heaven, and all this land that I have promised I will give to your offspring, and they shall inherit it forever."'" (Exodus 32:11-13)

Moses reminds God of his covenant with Abraham, Isaac, and Israel, and how he promised to multiply their descendants and give them the land. He pleads for God to show mercy and not destroy the Israelites, even though they have sinned greatly.

In response to Moses' intercession, the Lord relents from the disaster he had planned and does not destroy the people. However, there are still consequences for their sin, and Moses later confronts the people about their idolatry.

Moses' prayer for Israel's forgiveness is a powerful example of his role as an intercessor between God and the people. It shows his deep love and concern for the Israelites and his willingness to stand in the gap and plead for their forgiveness and restoration.