All sin is linked back to selfishness. ALL sin. There is no sin that we commit that won't come back to me being selfish. God sent Jesus to save us from our selfishness. We can only be pure by either avoiding selfishness all together (through obedience) or by God's grace. Thankfully, we all have God's grace because it is impossible to lack selfishness because we are disobedient more than obedient. Simply look at how we treat others around us. We don't treat people well. We are told to treat people well but we still won't. Because we are selfish.
Lord, thank You for Your saving Grace and please help me to be more obedient and less selfish than I was yesterday.