Psalm 65:3 (ESV)

3 When iniquities prevail against me, you atone for our transgressions.

The rains were proof that the Lord forgave the sins of Israel in fulfillment of the promise of Leviticus 26: “But if they confess their iniquity and the iniquity of their fathers in their treachery that they committed against me, and also in walking contrary to me, so that I walked contrary to them and brought them into the land of their enemies—if then their uncircumcised heart is humbled and they make amends for their iniquity, then I will remember my covenant with Jacob, and I will remember my covenant with Isaac and my covenant with Abraham, and I will remember the land” (Leviticus 26:40–42).