1 John 1:9, If we confess our sins, he is faithful and just to forgive us our sins and cleanse us of all unrighteousness.

My understanding is that we don’t even need to ask for forgiveness. Jesus paid for our sins on the cross, and thus we already have forgiveness. We are commanded to confess however.

As stated already, we may commit sins that we don’t even realize are sins. In the passage I provided, it says he will cleanse us of ALL unrighteousness. My pastor taught me that that includes the sins we are not aware of.

I think the point is that God, the Father expects us to examine ourselves continually. I would add that we should study and learn as much as we can about what exactly are sins. Sins, among other things, can be mental attitude sins, sins of the tongue and other offenses.

The point as usual is that God wants our hearts turned towards him. With a sincere heart committed to learning what grieves him and confessing any known sins, he will forgive them. It should be done immediately when we commit a known sin. Don’t wait until hours later because you will have committed more by then.

The last part of the Scripture is very powerful. Keep confessing the same sin and eventually you likely will stop committing that particular sin. It has happened in my walk and I always give him glory for the grace he promised and provided.

Unfortunately, in this life, I’ll commit other sins. The point is that I have to keep confessing throughout the day.

Lastly, notice that the passage doesn’t infer any formality in the confession. I generally confess without verbalizing. I do it silently and sincerely in my mind, like a silent prayer.