Augustine of Hippo

It is through grace that we not only discover what ought to be done but also that we do what we have discovered. That is, not only that we believe what ought to be loved but also that we love what we have believed. If this grace is to be called "teaching," let it at any rate be called "teaching" in such a manner that God may be believed to infuse it, along with an ineffable sweetness, more deeply and more internally. This teaching, therefore, would be not only by their agency who plant and water from without but likewise by God also who ministers in secret his own increase. All this is in such a way that God not only exhibits truth but likewise imparts love.… Thus the apostle speaks to the Thessalonians, "As touching love of the brothers, you have no need that I write to you, for you yourselves have been taught by God to love one another."