This is a question that is puzzling to many Bible students. Let us develop some foundational points that will help in supplying an answer to this question.
The Law of Moses
The Hebrew nation was organized officially at the time of its departure from Egypt. God brought this mighty body of people (of some two to three million souls) into the region of Sinai. There he gave them a written code to regulate their moral and religious activities.
The Ten Commandments constituted the core of that law. These rules, however, were buttressed with an extensive body of supplementary ordinances.
In addition, the Hebrews had living prophets who expanded God’s message to them along the way. The Mosaic regime provided for a specific sacrificial system for the Israelite people, by which means pardon from sin was bestowed in view of the coming Savior (see: Gal. 4:4; Heb. 9:15). Moreover, it embodied an elaborate system of worship.
In his letter to the Ephesians, Paul employed graphic imagery indicating the Mosaic law constituted a “middle wall of partition” that separated the Jews from the Gentiles (Eph. 2:14). The figure suggests a barrier that creates a distinction between two parties. Clearly, that vivid symbolism underscored the fact that the Hebrews and the Gentiles were not under identical religious systems.
Prior to the giving of the Mosaic law, the whole world was under what is commonly called Patriarchal law. The father of each household was the family priest, so to speak. He led the worship by the offering of sacrifices to God.
The Lord communicated directly with the people in various ways. Sometimes he did so by dreams (Gen. 31:11). Sometimes he employed visions (Gen. 46:2) or personal appearances (Gen. 18:1). And sometimes he appointed emissaries like Melchizedek (see Gen. 14:1ff; cf. also Heb. 1:1).
The patriarchal worship system is well illustrated in the lives of such men as Job (cf. 1:5) and Abraham (Gen. 12:8; 13:4, etc.). One historian has observed: “The concept of the patriarchal ‘God of the fathers’ is paralleled from the Old Assyrian tablets of the 19th century B.C. found in Cappacodia” (Yamauchi, 1290).
When the Hebrews were segregated from the balance of humanity as a “holy people” for Jehovah’s “own possession” (Dt. 7:6; 14:2), the Gentiles continued under the Patriarchal system until they were offered the gospel. The Patriarchal regime was replaced by the international Christian system (Acts 10).
Romans 1:18ff shows how those ancient Gentiles were accountable to God for their beliefs and conduct. Paul further amplifies the point in Romans 2:12-16 by suggesting that even the patriarchs, who had no written revelation from the Lord, possessed a sense of the difference between right and wrong (called “conscience”).
When they rejected what they knew to be right and embraced wrong, they stood condemned.
When the Gentiles sinned (and there can be no sin without law — Rom. 4:15; 1 Jn. 3:4), they were punished. Ultimately, those antique nations will be judged by the “light” which they possessed, and not by that which is available today through the Scriptures. Today, we are under a significantly greater measure of accountability in this age.
At times, certain Gentiles would join themselves to the Hebrews by means of the “proselyte” procedure. On the day of Pentecost, there were assembled at Jerusalem both “Jews and proselytes” (Acts 2:11; cf. 6:5; 13:43).
This meant that male Gentiles would receive circumcision, and all of the “converts” to the Israelite system would accept the responsibilities of the Mosaic law. There was even a place in the temple (called the Court of the Gentiles) to accommodate these adherents to Judaism.
Old Testament Emphasis
The Bible student must understand that the Old Testament gives much more prominence to the history of the Hebrew nation than it does to the religious conditions of the Gentiles. And there is a very good reason for this.
The Old Testament writers, under the guiding hand of God, principally were concerned with relating the story of the unfolding of Jehovah’s great plan of redemption to be consummated by the work of Christ.
Since the Lord was using the Israelite people in the implementation of his sacred purpose, it is understandable that more attention was given to these people and their worship practices, which were a “shadow of things to come” (Col. 2:17; cf. Heb. 8:5; 10:1) than to Gentiles.
This does not imply, however, that the Almighty was unconcerned with the Gentiles or that they were outside the pale of salvation. God’s rebuke of the nations through his prophets (cf. Amos 1; Jer. 46-51) bears ample testimony to their accountability to the Creator.
And Jonah’s missionary endeavor to the people of Nineveh in far-away Assyria is a delightful illustration of the Lord’s interest in Gentile people — even while the main focus remained upon the nation of Israel.