Note:
The difference between motivations based in the Law and motivations based in the Gospel is clear. The one is compulsion, the other is freedom. The one arises from fear, the other from love. The one from threats, the other from acceptance.

Quote:
“Obedience under the authority of Christ differs, therefore, from obedience under the law. The law as a law of retribution compels obedience because it offers hopes of reward and the threat of punishment. Motivation springs from a desire for self-preservation. Obedience under Christ’s authority, on the other hand, includes renunciation to the point of sacrifice of self. It is not enough to serve isolated commands, we must fit ourselves into the law of life of him who is the measure of all things. That requires faith, unconditional confidence in his person and his divine authorization.” (p. 248)

Source: Elert, Werner. The Christian Ethos. Philadelphia: Muhlenberg Press, 1957.