“Then the king of Assyria commanded, ‘Send there one of the priests whom you carried away from there, and let him go and dwell there and teach them the law of the god of the land.’ So one of the priests whom they had carried away from Samaria came and lived in Bethel and taught them how they should fear the LORD.” – 2 Kings 17:27-28
The people were taught the proper way to worship the Lord. They were, however, incorrectly placing Yahweh alongside their pantheon of deities. The Assyrian king recognized the futility of pluralistic worship and ordered an Israelite to return to Samaria to train the people how to properly worship God.
The similarities between these mandates from the Assyrian king and the Great Commission (Mat 28:18-20) are striking. Both the king, and later Christ himself, commanded disciples of God to both go and teach. Both the missionary sent by the king and the missionaries sent by Jesus are to live among the foreigners and are clearly instructed to teach law and exclusive worship of God. Missionaries are not instructed to teach western values, capitalistic theories, or pluralistic worship. God does not simply mandate worship. He demands worship of him alone. Ian Provan said, “As the only God there is, the LORD demands exclusive worship. He is not prepared to take his place alongside the gods, nor to be displaced by them. He will not be confused with any part of the created order.” Missionaries are sent to teach the undivided and proper worship of Yahweh.
The appropriate instruction of the law and worship of God cannot be accomplished in a week or by the showing of a native language film. Teaching the lost “all” (Mat 28:20) that Christ has commanded and teaching how to “fear the LORD” (2 Kings 17:28) requires missionaries to live among the people and invest time in biblical training and mentoring. This does not eliminate the value of mercy ministry or short-term missions, as long as those works are done in support of the instruction of the proper worship of God. Our God has been clear from the beginning. He is a jealous God and commands the exclusive worship of his name and no other belief or deity.
 I. W. Provan, “Kings,” ed. T. Desmond Alexander and Brian S. Rosner, New Dictionary of Biblical Theology (Downers Grove, IL: InterVarsity Press, 2000), 184.