In exploring this question today, "What is sin?" I want to begin with what you all know. You all know that sin is doing wrong. We all have a conscience, and we know when we have violated it. Often, we may not want to admit that we have done wrong. Nevertheless, Romans 

-15 speaks about how even people who do not know God's written law show that they have a sense of right and wrong. They show this by accusing others of wrong while trying to excuse themselves.

WSC Q15: The Sin by which Man Fell

The idea of imparting a body of truth (rudiments of the faith) is found repeatedly in scripture under many different terms and descriptions. We are not given a complete catechism or confession in the Bible. That is because we are to write our own according to the needs of the day. They must refute new heresies as they arise. Our Lord has called us to catechise in His church… to teach disciples the basics of the faith. Make the most of this instruction: memorise your Catechism, listen to the messages, and pray for the Spirit to work.