This... is God's hand, not ours, that we depart not from God.

This grace He placed "in Him in whom we have obtained a lot, being predestinated according to the purpose of Him who works all things." And thus as He works that we come to Him, so He works that we do not depart. Wherefore it was said to Him by the mouth of the prophet, "Let Your hand be upon the man of Your right hand, and upon the Son of man whom You made strong for Yourself, and we will not depart from You."

This certainly is not the first Adam, in whom we departed from Him, but the second Adam, upon whom His hand is placed, so that we do not depart from Him. For Christ altogether with His members is— for the Church's sake, which is His body— the fulness of Him. When, therefore, God's hand is upon Him, that we depart not from God, assuredly God's work reaches to us (for this is God's hand); by which work of God we are caused to be abiding in Christ with God— not, as in Adam, departing from God. For "in Christ we have obtained a lot, being predestinated according to His purpose who works all things."

This, therefore, is God's hand, not ours, that we depart not from God. That, I say, is His hand who said, "I will put my fear in their hearts, that they depart not from me." [Saint Augustine of Hippo; On Perseverance of all Saints, Ch 14]