The grace of God, actual or habitual is a created supernatural entity, beyond the scope of man's attainment, outside the limits of human exigencies.
It is wholly and entirely within God's power to dispense or withhold.
Good works cannot merit it; the most persistent natural desires cannot obtain it.
In the present providence of God, we are privileged to receive and use it, simply because God's liberality and Christ's redemption have come to the support of our natural helplessness for its attainment.
New Catholic Dictionary