Now what is this “circumcise the foreskin of your heart” business (Deuteronomy 10:16)? It sounds painful! Well, I guess it could be painful if you want to continue to cling to loving yourself. What it means is to dedicate yourself to a covenant relationship with God. It means putting your love for God and others before yourself. The New Testament is a new covenant, of course, and so the language used there to represent this concept is “crucify the flesh”.