When we repent of sin, God immediately forgives and forgets our sin. If that causes us to think that since God is so merciful and just, we can just go on and on sinning and sinning, Paul deals with that in Romans 6.

What shall we say then? Shall we continue in sin, that grace may abound?  God forbid. How shall we, that are dead to sin, live any longer therein?

Romans 6:1-2

God’s forgiveness toward us should usher into a new life, one where we can move on in the fullness of the life Christ died to give us, but that is often hindered because we are so self-centered that we allow our emotions of shame and remorse to dictate our actions. That always lead us into more sin. It’s like a fixed race. Because we don’t command our emotions to let go of repented sin, we are destined to repeat it. Think about that.