Reason Not To Sin - 1 Peter 1:13

Wherefore gird up the loins of your mind, be sober, and hope to the end for the grace that is to be brought unto you at the revelation of Jesus Christ;
1 Peter 1:13, KJV

Why not sin?

There is a grace to be brought to us at the revelation of Jesus Christ. When Christ appears, we shall be like him, 1 John 3:2 says. That's quite a grace! Right now we have tendencies to sin. On that day, however—no longer! So we are told to "perfectly hope" upon that grace. Think of what you will be! And it is God's love and grace that will bring that to pass without fail. 1 John 3:3 says that those who thus hope purify themselves. You can't think of sinning if you are in love with the God who will transform you into the likeness of Christ when he is revealed.