Book of Hosea Chapter 2 Vs. 23

 The Lord's Mercy on Israel

And I will sow her unto me in the earth; and I will have mercy upon her that had not obtained mercy; and I will say to them which were not my people, Thou art my people; and they shall say, Thou art my God. Hos. 2:23

I will sow... This pictures the sowing of Israel as a plant of His own in the earth, indicating their restoration (Hos. 1:10-11). This is why the word Jezreel (the seed of God which He will sow) is used in Hos. 2:22.

were not my... Quoted in Rom. 9:25, not of the Gentiles only, but as an illustration of what may be true in their case as well as in Israel’s (cp. 1Pet. 2:10).

This could be the wife of God, Israel, who had been rejected of God. All relations had become new. God is starting all over again with Israel. This could also, be speaking of the unbelieving world, which has been offered the opportunity to be God's people. Whosoever will, regardless of nationality or blood line, shall have the opportunity to be God's people, and Him be their God.

Rom. 3:29 "[Is he] the God of the Jews only? [is he] not also of the Gentiles? Yes, of the Gentiles also:"

Rom. 9:26 "And it shall come to pass, [that] in the place where it was said unto them, Ye [are] not my people; there shall they be called the children of the living God."

The Lord Himself is pictured as engaging in agricultural endeavors. He will plant Israel in the land (cf. see Hos. 1:2), where she will grow under His protective care. The nation called Lo-Ruhamah (not… loved; cf. Hos. 1:6) and Lo-Ammi (not My people; cf. Hos. 1:9) will experience God’s compassion and will be addressed as His people. They will acknowledge that He, not Baal, is their God. This passage is parallel to 1:10-2:1, where the same reversal in the significance of the symbolic names is seen.

Hos. 2:23, along with Hos. 1:10, is quoted in Rom. 9:25-26 and 1Pet. 2:10. Paul quoted those Hosea passages to say that both Jews and Gentiles will be converted during the Church Age (cf. Rom. 9:24). This does not mean, however, that he equated the Gentiles with Israel and regarded the conversion of Gentiles as a direct fulfillment of Hosea’s prophecy. Paul clearly taught that national Israel would be saved as well (Rom. 11:1-36). Rather, Paul extracted from Hosea’s prophecy a principle concerning God’s gracious activity (cf. F.F. Bruce, The Epistle of Paul to the Romans. Grand Rapids: Wm. B. Eerdmans Publishing Co., 1963, p. 196).

According to Hosea, God will mercifully bring a previously rejected people into a relationship with Himself. Paul recognized this same pattern in God’s dealings with the Gentiles. In Rom. 9:25 Paul, then, was applying Hos. 2:23 to the Gentiles; he was not reinterpreting the verse (cf. comments on Rom_9:24-26). Likewise Peter (1Pet. 2:10) saw the language of Hosea’s prophecy as applicable to New Testament believers, who by divine mercy have been brought into a relationship with God (cf. 1Pet. 1:3).