Sin is simply “to miss the mark.”
Sin is anything we do that is displeasing to God. We all miss the mark (that is, we all sin) at one time or another (Romans 3:23 and 1 John 1:10). Sins are implicitly unfaithfulness and hostility towards God (Leviticus 26:40).
This was the purpose of Jesus’ coming to earth: to die in place of all of us for the wrong things we have done. In essence, he paid our fine and did our time, so we won’t have to.
It’s easy to accept this gift (it’s free) and start on a journey with Jesus. Jesus simply said, “Come, follow me,” (Mark 1:17).