For K, I want to be brief and simple. Romans 8:12-13 says, “So then, brethren, we are under obligation, not to the flesh, to live according to the flesh – for if you are living according to the flesh, you must die; but if by the Spirit you are putting to death the deeds of the body, you will live.”
This truth is clear, if we live according to our fleshly desires we will die, and go to hell. But if we, by the Spirit, put to death the deeds of the body, we will live. We’ve got an enemy who does not want us to be holy, therefore we must kill sin if we’re to be triumphant over sin.
To help you out with this, to teach how to do this well, I cannot recommend John Piper’s sermon series “How to Kill Sin” enough. It is awesome, and you can listen to all three by clicking here (all three are about half way down in this list).