Nationally, Israel was a religious-political entity—a theocracy, a God-ruled institution. Israel was basically a governmental entity that had a very wide social dimension much of which was peculiar to the nation. The Law of Moses expressed the divinely-given legal covenant that forged the Hebrew tribes into a kingdom of priests (Exod 19:6); it codified the constitution of the state of Israel in Old Testament history. It was an indivisible law code (James 2:10) that consisted of three aspects: moral, civil, and ceremonial. The Law of Moses uniquely belonged to Israel, not to the Gentile nations (Rom 2:14), and it was incumbent only on the covenant community.
Thus the questions are raised: Were the social demands of the Law to be imposed by Israel on the surrounding nations, and were those nations required to adopt the Mosaic Covenant as their own political infrastructures? The answers are plainly negative. The covenant obligations, including its social demands, were to be internalized by Israel alone and by those admitted to the covenant community through the required Levitical procedures. Israel did not have a mandate to establish Mosaic social justice world-wide.
In ancient Israel the civil and the religious arenas were combined in the theocratic polity, in effect a union of church and state. The Law governed every aspect of the people’s lives including the social sphere, and this in part sets the Old Testament people of God apart from the New Testament church.
Rolland McCune, Promise Unfulfilled: The Failed Strategy of Modern Evangelicalism, 262.