We do obey Him. By daily dying to ourselves and living for Him, by the power of the Holy Spirit working in us. Your acting as if by saying "It is by Christ that we are saved" that I am somehow saying that we should not walk in obedience and that is not true. The very word of God says it is by Christ that we are saved and it also says to walk in obedience. Both verses are Truth. None more than another. The whole word works together. It also says it is not by mans efforts that he is saved, and to watch your life and doctrine closely and guard the good deposit. God does not contradict himself all these verses work together and it can not be understood with our natural man and his mind, but by the Spirit and with the mind of Christ. Therefore it is him working in us to will and to act. Not by the power of men but by the power of God.
"Therefore, my dear friends, as you have always obeyed—not only in my presence, but now much more in my absence—continue to work out your salvation with fear and trembling, 13for it is God who works in you to will and to act in order to fulfill his good purpose."
Philippians 2:12-13
We should be as David before God
1Have mercy on me, O God,
according to your unfailing love;
according to your great compassion
blot out my transgressions.
2Wash away all my iniquity
and cleanse me from my sin.
3For I know my transgressions,
and my sin is always before me.
4Against you, you only, have I sinned
and done what is evil in your sight;
so you are right in your verdict
and justified when you judge.
5Surely I was sinful at birth,
sinful from the time my mother conceived me.
6Yet you desired faithfulness even in the womb;
you taught me wisdom in that secret place.
7Cleanse me with hyssop, and I will be clean;
wash me, and I will be whiter than snow.
8Let me hear joy and gladness;
let the bones you have crushed rejoice.
9Hide your face from my sins
and blot out all my iniquity.
10Create in me a pure heart, O God,
and renew a steadfast spirit within me.
11Do not cast me from your presence
or take your Holy Spirit from me.
12Restore to me the joy of your salvation
and grant me a willing spirit, to sustain me.
13Then I will teach transgressors your ways,
so that sinners will turn back to you.
14Deliver me from the guilt of bloodshed, O God,
you who are God my Savior,
and my tongue will sing of your righteousness.
15Open my lips, Lord,
and my mouth will declare your praise.
16You do not delight in sacrifice, or I would bring it;
you do not take pleasure in burnt offerings.
17My sacrifice, O God, is a broken spirit;
a broken and contrite heart
you, God, will not despise.
God wants those who are willing so that he might work in us for His purpose. It is not by our own power but His alone, if we are willing to die. This is something we must choose to do daily...empty ourselves of what is detestable to God so that He may live in and through us. Are daily prayer should be that of David's....a man who longed to be separate and holy...fit for His use.