The Apostle Paul says, "Circumcision is that of the heart." We become sanctified and righteous by believing in the heart, not according to the deeds of the outer men. Sanctification does not depend on whether our outer men do as God says or not. Do you understand this? The problem is that we have both the outer and inner selves and they coincide. Therefore, we sometimes tend to place more weight on the outer man. We become confident if our outer selves do well, but disappointed if they don't. Paul says this is not the right faith.

"Circumcision is that of the heart." What is the real truth? How do we know and believe with the heart? In Matthew 16, Jesus asked Peter, "Who do you say that I am?" Then Peter confessed his faith, saying, "You are the Christ, the Son of the living God." Peter believed like that with the heart. Jesus said, "Blessed are you, Simon Bar-Jonah, for flesh and blood have not revealed this to you, but my Father who is in heaven." Jesus said Peter's faith was right.

Jesus took away all our sins through His baptism and blood, we are saved in our hearts, pray to God with our hearts, the faith lives in our hearts :
"For with the heart one believes unto righteousness, and with the mouth confession is made unto salvation." Romans 10,10