These two passages from Paul are precious to me:
Therefore, my beloved, as you have always obeyed, so now, not only as in my presence but much more in my absence, work out your own salvation with fear and trembling, for it is God who works in you, both to will and to work for his good pleasure. (Php 2:12-13 ESV)
But by the grace of God I am what I am, and his grace toward me was not in vain. On the contrary, I worked harder than any of them, though it was not I, but the grace of God that is with me. (1Cor 15:10 ESV)
I must work hard—but in the end I must look back and confess with joy that God was the one who was at work in any good I did.
Slavery to this Master is true freedom, because He commands only good and He gives what He commands.