Exodus 23:21

23:21 Take heed because of him, and obey his voice; do not rebel against him, for he will not pardon your transgressions, for my name is in him.

Exodus 34:9

34:9 and said, “If now I have found favor in your sight, O Lord, let my Lord go among us, for we are a stiff-necked people; pardon our iniquity and our sin, and take us for your inheritance.”