Flawless people have no need of grace or mercy.
My track record shows that I am far from perfect. I regularly have to ask for forgiveness. I regularly find myself hoping for mercy.
If you think about your life like school, imagine that you’re doing a group project with Jesus. You do “C” work and he does “A+” work. Your grade improves because he exceeded the standard. Someone else went the extra mile and saved your grade when your personal efforts didn’t get you the desired result.