There must be compatibility between grace and obligation...

There must be compatibility between grace and obligation, because grace plays as a motivator and its being a motivator with respect to the obligation depends on the existence of compatibility between them, and there must be no disconnection [between them]. The obliged person must be aware of the grace because without such awareness, grace cannot function as a motivator. Of course, in this regard, synoptic knowledge is also enough.

For example, he must be aware that some hardships and afflictions he is experiencing are due to his inattention to God and his continued indulgence in sins. ^10 Reasons behind the Necessity for Grace The proof of wisdom The most prominent rational proof of the incumbency of grace upon God is the principle of the Divine wisdom in the sense that abandonment of grace necessitates reversal of the motive which, in turn, is incompatible with wisdom, and it is invalid.