For though your people Israel be as the sand of the sea, yet a remnant of them shall return: the destruction decreed shall overflow with righteousness.
Read Chapter 10
Ambrose of Milan
This, then, is what the patriarch Isaac says, “You shall serve your brother. But the time will be when you shall shake off and loose his yoke from your neck.” He means that there will be two peoples, one the son of the slave girl, the other of the free woman—for the letter is a slave, whereas grace is free. The people that is attentive to the letter is going to be a slave as long as it needs to follow the expounder of learning in the spirit. Then that will also come to pass what the apostle says, “that the remnant may be saved by reason of the election made by grace.” “You shall serve your brother,” but then you will perceive your advancement in servitude only when you begin to obey your brother voluntarily and not under compulsion. - "Jacob and the Happy Life 3.13"
The remnant means the Jews who have believed in Christ. Many of them, we remember, did believe in the days of the apostles, and even today there are some converts, although very few. - "City of God 17.5"
May the remnant be saved, as Isaiah said, “and the remnant has” clearly “been saved.” For out of them were the twelve apostles, out of them more than five hundred brothers, to whom the Lord showed himself after his resurrection. Out of their number were so many thousands baptized, who laid the price of their possessions at the apostles’ feet. Thus then was fulfilled the prayer here made to God: “For your servant David’s sake, turn not away the presence of your anointed.” - "Explanations of the Psalms 132 (131):10"
Through this Son of man, Christ Jesus, and from his remnant, that is, the apostles and the many others who from among the Israelites have believed in Christ as God, and with the increasing plenitude of the Gentiles, the holy vineyard is being completed. - "In Answer to the Jews 6"
And it is their own Scriptures that bear witness that it is not we who are the inventors of the prophecies touching Christ. That is why many of them, who pondered these prophecies before his passion and more especially after his resurrection, have come to believe in him, as was foretold: “For if your people, O Israel, shall be as the sand of the sea, a remnant of them shall be converted.” - "City of God 18.46"
Converted. This was partly verified in the children of Israel who remained after the devastations of the Assyrians, in the time of king Ezechias: and partly in the conversion of a remnant of the Jews to the faith of Christ. (Challoner)
4 Kings xviii. 3., and Romans ix. 27. The apostle follows the Septuagint, (Calmet) "and if the people of Israel be. "
Converted. Septuagint, "saved, for perfecting the word and abridging in justice. Because God, the Lord of hosts, will make an abridged word in the universe. "(Haydock)
As the apostle has explained this passage, "every other interpretation must cease. "(St. Jerome)
The few who were converted under Ezechias were a figure of those who should embrace the faith of Christ. (Calmet)
Consumption. That is, the number of them cut short, and reduced to few, shall flourish in the abundance of justice. (Challoner)
Hebrew, "the desolation is decreed, justice shall overflow. "God will treat all with rigour, Nahum i. 8. The incredulous Jews shall be...
But grace from above sometimes looks upon these mighty men and afflicts them by the very employments caused by their abundant goods and intersperses with their prosperity adverse but profitable tribulation. [This is done] in order that, being sorrowful, they may turn to their heart and learn how vainly they are engaged in perishable pursuits.… This can be especially understood also of the Jews.… Because they are to be admitted to the faith at the end of the world … it is said by Isaiah, “if the number of the children of Israel shall be as the sand of the sea, a remnant shall be saved.” For the light returns to them when they themselves return to confess the power of our Redeemer. - "Morals on the Book of Job 5.27.25–26"
Do you also see that he does not say that all will be saved but only those who are worthy will be saved?… He does not speak of the “sands of the sea” without cause, but he does so to remind them of the ancient promise they had made themselves unworthy of. Why are you bothered, as though the promise has not been kept? The prophets demonstrate that not everyone will be saved.… It not only demonstrates that only a few will be saved, and not everyone, but also says how they will be saved. How are they to be saved, and by what manner will God consider them to be worthy?… Faith is such that it holds salvation in a few short words. - "Homilies on Romans 16.9"