QUESTION: What is sin?
ANSWER: Sin is a transgression (breaking or violation) of the law (I John 3:4). All unrighteousness is sin (I John 5:17). To know to do good and not do it is sin (James 4:17). When one conducts himself so that he violates the Word of God, he sins. It may be a deed done, or it may be something left undone.
Sin causes spiritual death (Ephesians 2:1), which is separation from God (Isaiah 59:1-2). It must be removed in order for the sinner to be (saved) reconciled to God (II Corinthians 5:20). Christ shed His blood in order that our sins might be (removed) washed away (Revelation 1:5). Many passages tell us what we must do in order to be washed in His blood! See Mark 16:16; Acts 2:38; Acts 22:16; I Peter 3:21.