The Rock of Israel - The Fountain whence Israel was derived.

He that ruleth over men must be just - More literally, מושל באדם צדיק moshel baadam tsaddik, He that ruleth in man is the just one; or, The just one is the ruler among men.

Ruling in the fear of God - It is by God's fear that Jesus Christ rules the hearts of all his followers; and he who has not the fear of God before his eyes, can never be a Christian.

The God of Israel said,.... To David, or by him; he who was the covenant God of Israel literally considered, and is the covenant God and Father of the whole spiritual Israel, and who is owned, believed in, and worshipped by them:

the Rock of Israel spake to me; the same with the God of Israel in other words, who is the strength and security of Israel; or the second divine Person, the Son and Word of God, is meant, who is often called a rock in Scripture; and is the rock on which the Israel or church of God is built, and in whom it remains safe and firm, the gates of hell not being able to prevail against it; and so here is an instance and proof of a trinity of persons in the Godhead; the God of Israel, Jehovah the Father; the Rock of Israel, Jehovah the Son; and the Spirit of Jehovah, as in Sa2 23:2, who is Jehovah the Spirit: now what was said by these three divine Persons to David, and by him, and concerning himself as a type of the Messiah, follows:

he that ruleth over men must be just, ruling in the fear of God; which is a character every king among men ought to have, administering justice to their subjects; ruling not only according to the laws of the land, but according to the law of God; having his fear before their eyes, and acting with a view to his honour and glory, whose vicegerents they are, and to whom they are accountable; they should rule with gentleness and humanity, considering they are men, and not brutes, they rule over. Agamemnon in Homer is often called "king of men". This character, in all respects, was found in David, Sa2 8:15; and may be here given as an instruction to his son and successor, Solomon; and is in all respects applicable to the Messiah, who is a "ruler" or King by the designation of his father; a ruler "over men", even over all men, yea, over the greatest of men, King of kings, and Lord of lords, and especially, and in an eminent sense, King of saints; and he is "just", a King that reigns in righteousness, righteous in all his ways and works, and particularly just as a King, as well as in all his other characters, see Jer 23:5; and upon whom, as man and Mediator, the Spirit of "the fear of the Lord" rests, and under the influence of which, as such, he has acted, Isa 11:1; so the Targum applies these words to the Messiah thus,"the true Judge said, he would appoint to me a King, who is the Messiah, who shall arise and rule in the fear of the Lord:''and they may be rendered, there shall be "a ruler over men, just, ruling in the fear of God"; or ruling, appointing, ordering, and directing the worship of God, and the ordinances of it under the Gospel dispensation, as Christ did, see Mat 28:18.