“Our fathers, when they were in Egypt, … did not remember the abundance of your steadfast love, but rebelled by the sea, at the Red Sea. Yet he saved them for his name's sake, that he might make known his mighty power” (v7-8). The Israelites weren’t worshipping the God of Abraham when they were slaves in Egypt, yet God miraculously delivered them anyway. He guided them through the desert, though they “murmured in their tents and did not obey the voice of the Lord” (v25). He wanted them to trust Him as Savior (v21)
God loves us and forgives us not because we live up to His expectations, but “according to the abundance of His steadfast love” (v45).