From ver. 5 onwards, the king lays down the principles of his public action, and that mainly in reference to bad men. One verse suffices to tell of his fostering care of good men. The rest describes how he means to be a terror to evil-doers. The vices against which he will implacably war are not gross crimes such as ordinarily bring down the sword of public justice. This monarch has regard to more subtle evils--slander, superciliousness, inflated vanity ("proud-hearted" in ver. 5 is literally wide in heart, _i.e._ dilated with self-sufficiency or ambition). His eyes are quick to mark "the faithful in the land." He looks for those whose faithfulness to God guarantees their fidelity to men and general reliableness. His servants shall be like himself, followers of "the way of perfectness." In that court, dignity and office will go, not to talent, or to crafty arts of servility, or to birth, but to moral and religious qualities.
In the last two verses, the psalm returns to evil-doers. The actors and speakers of lies shall be cleared out of the palace. Such base creatures crawl and sting about the purlieus of courts, but this prince will have his immediate _entourage_ free from them. He longs to get rid of the stifling atmosphere of deceit, and to have honest men round him, as many a ruler before and since has longed. But not only palace, but city, has to be swept clean, and one cleansing at the beginning of a reign will not be enough. So "every morning" the work has to be done again. "Ill weeds grow apace," and the mower must not get weary of his scythe. God's city must be pure. "Without are ... whatsoever worketh and maketh a lie."
The psalm is a God-given vision of what a king and a kingdom might and should be. If David wrote it, his early resolves were sadly falsified. "I will set no villainous things before my eyes"--yet from his "house," where he vowed to "walk with a perfect heart," he looked on Bathsheba. "He that speaks lies shall not be established in my sight"--yet Absalom, Ahithophel, and the sons of Zeruiah stood round his throne. The shortcomings of the earthly shadows of God's rule force us to turn away to the only perfect King and Kingdom, Jesus Christ and His realm, and to the city "into which shall in nowise enter anything that defileth."