Paul stresses it is the faith OF Christ that we are to live by; it is the faith OF Christ that justifies. Human faith is weak sometimes; His faith is complete, perfect! The miracle of redemption comes through grace; every miracle in this realm comes through grace not works. I want to live a miracle-revealing life, don't you? We can only do that with HIS faith!
The Law is a shelter, a guide that shows us what God looks like...it is the shadow of the real thing: Jesus Christ. The purpose of the Law is to draw us to the One who is the perfect fulfillment. Jesus did not cancel out the Law, His faith fulfilled it! We will not live lawless if we rely on His faith but if we try to 'do the Law' on our own, we simply prove our sinfulness. Seeking to serve the Law in our flesh leaves us sin-filled. Seeking to serve the Lord puts us in the shelter rather than the shadow!
Grace is what brings us into the faith of Christ; we cannot enter His faith through works. Therefore, the life of faith does not have a list of 'do and do not.' That is great news for me because rules rile me up. If I am told, you cannot, I immediately want to do it. The life of faith, though, is not lawless. There are clearly things we will (and will not) do when we live in grace. The undeserved favor (GRACE) that allows me to live in His faith demands I ask what His heart is for me in every situation. The Spirit will never lead me into actions that do anything other than reveal HIM...the fulfillment of law. My works will then produce a beauty of grace that draws others to His faith.
The closest thing to a 'to do list' in the life of faith is this:
Living by His faith, serving Love, allows others to see Christ too. His faith works by love to fulfill the Law. Shine, Jesus, shine!