Salvation is the process of sanctification by the Spirit (2 Thess. 2:13) in which we are being changed into the likeness of the Lord "from one degree of glory to another" (2 Cor. 3:18).
Salvation is certainly a matter of God's ever-flowing grace and not something that can be ours through the exercise of our own power (Ephesians 2:8). Yet, faithful acceptance of God's grace does not rule out the necessity for works (James 2:17).
The false antithesis between grace and works is resolved with the realization that the works evident in the lives of those who are being sanctified in the salvation process are the works of the Spirit. For, every good thing is an act of God (Matthew 19:17).
Thus, reincarnation need not be viewed as a karmic process of self-righteousness, but as a process of salvation in which the Spirit of Christ brings us to His bossom through our faithful acceptance of His graceful efforts!
An understanding of reincarnation that is grounded in the Christ Revelation that God is Love is not inconsistent with a true Christian understanding of Divine Grace.
Karmic consequence is not the result of self-works. But, it functions with regard to our receptivity of God's enabling Spirit. Grace is fundamentally necessary for there to be salvation, but, grace must be freely received. It must be acknowledged and accepted.
Free Will and Grace are the two poles of the salvific process!