From Commentary on Psalm 109, (ca. 420)
God promised eternal salvation, everlasting happiness with the angels, an unfading inheritance, endless glory, the joyful vision of his face, his holy dwelling in heaven, and after our resurrection from the dead, the assurance of no further fear of death. This is (so to speak) his final promise toward which all our intentions should be focused; for when we have reached it, we shall require nothing more nor demand nothing more.
Furthermore, Our Lord also manifested in his promises and prophecies the way in which we would arrive at our final goal. He promised humans divinity, mortals immortality, sinners justification, the poor a rising to glory. Whatever he promised, he promised to those who were unworthy, so that it was not a case of a reward being promised to workers, but of grace being given as a gift, as its name implies.
Hence, even those who live justly, insofar as men and women can live justly, do so not through human merits but through grace. No one lives justly unless that person has been justified that is, been made just, and one is made just by him who can never be unjust. As a lamp cannot light itself, so the human soul does not enlighten us, but rather calls out to God, “O Lord, give light to my lamp.”
But, my beloved, because God’s promises seemed impossible to us — equality with the angels in exchange for mortality, corruption, poverty, weakness, dust, and ashes — God not only made a written contract with us to win our belief, but also established a mediator of his good faith; not a prince or angel or archangel, but his only Son. He wanted, through his Son, to show and give us the way he would lead us to the goal he has promised.
It was not enough for God to make his Son our guide to the way; he made him the way itself, that we might travel with him as leader, and by him as the way.
Therefore, the only Son of God was to come to us, to become human, and to our nature to be born as one of us, to die, to rise again, to ascend into heaven, to sit at the right hand of the Father and to fulfill his promises among the nations; and to fulfill his promises among the nations; and after that to come again, to exact now what he asked for before, to separate those deserving his anger from those deserving his mercy, to execute his threats against the wicked, and to reward the just as he had promised.
All this had to be prophesied, foretold, and promised as an event in the future so that it would not inspire fear by coming suddenly but would be believed in and expected.
St. Augustine (354-430) was a theologian and philosopher who served as Bishop of Hippo Regius in North Africa. He was a voluminous author, whose writings about God’s grace, the Sacraments, and the Church have been profoundly influential in the development of Western Christianity. His extensive commentary on the Psalms, a collection of expository sermons, was completed in about 420. His feast day is August 26.