John Gill's Exposition of the Whole Bible
Hosea 1:10
Yet the number of the children of Israel shall be as the sand of the sea, which cannot be measured nor numbered,.... Though called Loammi, and rejected from being the people of God; yet there is a time when their number, according to the promise made to Abraham, shall be as the sand of the sea, and the stars of heaven; which, as the one cannot be measured, the other cannot be numbered; which was to be not at the return of the Jews from the Babylonish captivity, when some of the ten tribes of Israel returned with them, as Theodoret and others think; for they were but few that then returned: but rather at the first times of the Gospel, when multitudes that came from various parts of the world were converted at the day of Pentecost, and greater numbers; who were met with in the ministry of the word, in the various parts of the world, where they were dispersed, and the Gospel came, to whom Peter and James wrote their epistles; and not these only are meant, but the vast numbers of Gentiles, who were effectually called by grace everywhere, and were true Israelites, the spiritual seed of Abraham; and to whom the Apostle Paul applies these words, producing them as a testimony of the election and calling, not of the Jews only, but of the Gentiles also, Romans 9:24, and which will have a further accomplishment in the latter day, when the fulness of the Gentiles will be brought in, the Jews will be converted, and all Israel saved, Romans 11:25, then the numbers of the Israel of God, both of Jews and Gentiles, will be as the sand of the sea indeed!
and it shall come to pass, that in the place where it was said unto them, ye are not my people, there it shall be said unto them, ye are the sons of the living God; that is, in such places where it used to be said, here live Pagans, Turks, or Jews, who worship not the true God, or at lease not aright, nor believe in Christ, and profess his name; "there it shall be said to them", by the Lord himself, by his Spirit witnessing their relation to them, and by all good men, and even by the world in general; not only that they are "the people of God", but have a superior privilege, a greater character, and a higher relation, the sons of the living God; the sons of God, not by nature, as Christ; nor by creation, as angels; nor by office, as civil magistrates; or by profession merely, as nominal Christians; but by adopting grace; which exceeds all other blessings, even of sanctification and justification; makes men honourable; is attended with various privileges, and always continues. The epithet "of the living God" is not without cause put; it stands in opposition to dead idols before worshipped by some who will now be the children of God; and who, as he has life in himself, gives it to others; to all natural life and breath, and to his children spiritual and eternal life; and, as he lives forever, so shall they his sons likewise. The Targum is,
"and it shall be in the place where they have been carried captive, when they transgressed the law; and it was said to them, ye are not my people; there they shall be converted and increased (or made great); and it shall be said to them, O ye people of the living God.''