I don’t want to beat you up or anything. Please note, it is not contradictory in the slightest. When you accept Christ’s work on the cross, His blood is what covers your sin. When the Heavenly Father looks upon you he will see His Son’s blood. That is the payment for our sins. Nothing else would suffice.
Fine, that’s what you believe, I believe I will go to purgatory if I am not sinless when I die.