But he shall not multiply horses to himself, nor cause the people to return to Egypt, to the end that he should multiply horses: forasmuch as the Lord hath said unto you, Ye shall henceforth return no more that way. (Deuteronomy 17:16)
Egypt was recognized as a source of supply for horses (1 Kings 10:28, 29). The command means that agents were not to be sent to Egypt to buy horses.
Here again Solomon greatly sinned. As a matter of fact, the topography of Palestine, being mountainous, did not lend itself readily to the movement of large bodies of horsemen. Therefore to build up a large force of cavalry would mean alliances with outlying nations and reflect a desire to conquer adjacent territories. The spiritual destiny of Israel would be lost in the desire for worldly conquest.
Not multiply horse.
Solomon did not heed this command (1 Kings 4:26). Dependence upon cavalry indicated a lack of faith in the power of God to keep His people. This usually accompanied a lapse into rebellion and sin (see Isa. 2:6-8; Amos 4:10).