Luther says to form Christ within ourselves

I was reading Luther's treatise on good works, and I found this passage:

Lo! thus must thou form Christ within thyself and see how in Him God holds before thee and offers thee His mercy without any previous merits of thine own, and from such a view of His grace must thou draw faith and confidence of the forgiveness of all thy sins. Faith, therefore, does not begin with works, neither do they create it, but it must spring up and flow from the blood, wounds and death of Christ. If thou see in these that God is so kindly affectioned toward thee that He gives even His Son for thee, then thy heart also must in its turn grow sweet and kindly affectioned toward God, and so thy confidence must grow out of pure good-will and love -- God's love toward thee and thine toward God. We never read that the Holy Spirit was given to any one when he did works, but always when men have heard the Gospel of Christ and the mercy of God. From this same Word and from no other source must faith still come, even in our day and always. For Christ is the rock out of which men suck oil and honey, as Moses says, Deuteronomy xxxii.

(Emphasis added)

The link can be found here:

http://www.bibleteacher.org/luthergd_2.htm

It seems incongruent with his other writings, as well as with Lutheranism in general. I think there is something idiomatic going on there, but I am not sure. If someone can enlighten me, I would appreciate it.