I have 11 pages of thick notes that I have compiled on the core of Christian motivation, among many fundamental concepts, here is a primary one:
God. God is my motivation. God's Glory, God's Grace, His "Person", God's Attributes, God's Presence.
Angels cry day and night, "Holy, Holy, Holy", there motivation is NOT based on the reactions of other angels, or mankind, nor of even a reaction from God Himself. Merely the Holiness of God and the Presence of God's "Person and Being" ... See Moremotivates them, yea utterly compels them to bear their testimony aloud. May we do the same, by beholding the person of Jesus by faith alone, by grace alone, by the Power of the Holy Spirit alone.
Php 2:13 for it is God who works in you, both to will and to work for his good pleasure.