John Cassian

God brings salvation to the human race in diverse and innumerable methods and inscrutable ways. He stirs up some, who already want it and thirst for it, to greater zeal, while other even in their resistance, he forces against their will. Sometimes he gives his assistance in the fulfillment of those things which he sees that we desire for our good, while at other times he instills in us the beginnings of holy desire and grants both the beginning of a good work and perseverance in it.… The blessed apostle, reflecting on the manifold bounty of God's providence as he sees that he has fallen into some vast and boundless ocean of God's goodness, exclaims: "O the depth of the riches of the wisdom and knowledge of God! How inscrutable are the judgments of God and his ways past finding out! For who hath known the mind of the Lord?" Whoever then imagines that he can by human reason fathom the depths of that inconceivable abyss, will be trying to explain away the astonishment at that knowledge, at which that great and mighty teacher of the gentiles was awed. For if a person thinks that he can either conceive in his mind or discuss exhaustively the designs of God through which he brings salvation to human beings, he certainly impugns the truth of the apostle's words and asserts with profane audacity that his judgments can be scrutinized and his ways searched out. The Lord also witnesses to this when he says, "For my thoughts are not your thoughts, neither are your ways my ways."