St. Augustine: For a man's good will comes before many other gifts from God...

For a man's good will comes before many other gifts from God, but not all of them. One of the gifts it does not antedate is -- just itself! Thus in the Sacred Eloquence we read both, "His mercy goes before me," and also, "His mercy shall follow me." 

It predisposes a man before he wills, to prompt his willing. It follows the act of willing, lest one's will be frustrated. Otherwise, why are we admonished to pray for our enemies, who are plainly not now willing to live piously, unless it be that God is even now at work in them and in their wills? Or again, why are we admonished to ask in order to receive, unless it be that He who grants us what we will is he through whom it comes to pass that we will? 

We pray for enemies, therefore, that the mercy of God should go before them, as it goes before us; we pray for ourselves that his mercy shall follow us.

St. Augustine