I was reading in Mark chapter 8 just now where Jesus rebukes Peter and tells him that he is acting like satan. I read the verse after that and it struck a chord in my brain. Jesus says "For you are not setting your mind on the things of God, (things of the Spirit) but on the things of man (things of the flesh).
I was reminded of what Paul said in Romans chapter 8, that setting the mind on the flesh is death, but setting the mind on the Spirit is life and peace. Peter wasn't stealing, practicing sexual immorality or any of those things. He was simply trying to protect Jesus, trying to be the rock. But instead Jesus called him satan.
It's interesting that Paul says, "if you live according to the flesh you will die, but if by the Spirit you put to death the deeds of the body, you will live."
How does a Christian die when Christ has saved him? Apparently we aren't talking about losing salvation or dying physically, but I think he means death as in denying the life that comes from the Spirit and working out of the flesh. Notice he uses two different words, "flesh" and "body". He uses flesh to describe self-effort, and deeds of the body to describe sin.
So, we must deny self, (flesh) take up our cross, (consider ourselves dead to sin) and follow Jesus (set our minds on the Spirit). "For all who are LED (seems like we're following someone) by the Spirit are sons of God. "For we did not receive the spirit of slavery to fall back into fear, but we have received the Spirit of adoption as sons, by whom we cry, 'Abba! Father!'"
This still isn't crystal clear to me, as I'm sure it isn't to anyone who might read this, but I think I am catching on a little more.