I hate the assembly. The Psalmist protests again how greatly he abhorred the ungodly. Formerly he denied that he had any fellowship with them; now he still more explicitly declares that he fled from their company with loathing, for that is the meaning of the phrase, I hate. It is indeed true, that the wicked are everywhere hated; but how few withdraw themselves from them, that they may not imitate their vices! David asserts both; he tells us that he hated their society, and that he had no communion with them, from which it appears that he warred not so much with their persons as with their evil doings. He mentions also as another qualification, that he shunned the wicked in such a manner as not on that account to forsake the congregation of God, or withdraw himself from the company of those with whom he was commanded by divine appointment to associate. Many err in this way grievously; imagining when they see the evil mingled with the good, that they will be infected with pollution, unless they immediately withdraw themselves from the whole congregation. This preciseness drove the Donatists of old, and prior to them the Cathari and the Novatians, into mischievous schisms. In our own times, too, the Anabaptists, from a similar conceit, have separated themselves from the sacred assemblies, because they reckoned them not so free from all defilement as could have been wished. Moreover, the Donatists made themselves a laughing-stock in a certain process, by tenaciously clinging to mere words. When an assembly was held to settle dissensions, and they were invited by the president of the meeting, with a view to do honor to them, to take a seat, they replied, they would stand, because it was not lawful to "sit with the wicked." Why then, wittily replied Augustine, did your conscience permit you to come in amongst us? for the one is written as well as the other, I will not go in to the wicked, neither will I sit with the ungodly. David, therefore, prudently moderates his zeal, and while separating himself from the ungodly, ceases not to frequent the temple, as the divine commandment and the order prescribed in the law required. When he denominates them the assembly of the ungodly, we may unquestionably conclude, that their number was not few; nay, it is probable that they flaunted about at that time, as if they alone were exalted above the people of God, and were lords over them: yet this did not prevent David from coming as usual to the sacrifices. Public care, indeed, is to be used that the Church be not defiled by such wickedness, and every man ought privately to endeavor, in his own place, that his remissness and forbearance do not cherish the disorders which these vices occasion. Although, however, this strictness should not be exercised with that care which is necessary, there is nothing in this to hinder any of the faithful from piously and holily remaining in the fellowship of the Church. It is to be observed, in the meantime, that what retained David, was his communion with God and with sacred things.

I have hated - We have here the same evidence of his piety repeated in another and a stronger form. In the previous verse he had merely stated that he had not been found among that class of persons, or that he had not made them his companions. He here says positively that he disapproved of their principles; that he hated the purpose for which they gathered themselves together; that he had no sympathy whatever with them.
The congregation of evil-doers - All such assemblages as were gathered together for wicked purposes, for sin and revelry; to plot wickedness; to injure men; to oppose God.
And will not sit with the wicked - That is, I will not be associated with them. This was the fixed purpose of his soul; and this was then, as it is now, an evidence of true piety. This, moreover, is an "indispensable" evidence of piety. He who does thus sit with the wicked; who makes them his companions and friends; who unites with them in their plans and purposes; who partakes with them in their special amusements and pursuits, cannot possibly be a pious man. If he mingles with such people at all, it must be only as demanded by the necessities of social or civil life; or in the transactions of business; or for the purpose of doing them good. If it is for other purposes, if he makes them his chosen companions and friends, he gives the clearest evidence that his heart is with them, and that it is not with God.

I have hated the congregation of evil doers - I have never made one in the crowds of discontented persons; persons who, under pretense of rectifying what was wrong in the state, strove to subvert it, to breed general confusion, to overturn the laws, seize on private property, and enrich themselves by the spoils of the country.

I have hated the congregation of evildoers,.... That do harm to the persons, characters, or properties of men; and who meet together in bodies, to consult and form schemes to do mischief, and have their assemblies to encourage each other in it; these, their works and actions, the psalmist hated, though not their persons; and showed his displicency at them, and dislike and disapprobation of them, by absenting from them; see Jeremiah 15:17;
and will not sit with the wicked; ungodly and unrighteous men, sons of Belial; for with such what fellowship and concord can there be? 2-Corinthians 6:14; the word (x) signifies restless and uneasy persons, who cannot rest unless they do mischief; are like the troubled sea, continually casting up mire and dirt, Isaiah 57:20; now, by all this the psalmist means not that good men should have no manner of conversation with the men of the world: for then, as the apostle says, we must needs go out of the world, 1-Corinthians 5:9. Conversation in civil things, in matters of trade and business, is lawful; though all unnecessary conversation in things of civil life is to be shunned; no more should be had than what natural relation and the business of life require; but all conversation in things criminal is to be avoided; company is not to be kept with them, so as to join them in anything sinful; this is to harden them in their evil ways, and it brings into danger and into disgrace: a man is known and is judged of by the company that he keeps; and evil communications corrupt good manners.
(x) "significat inquietum esse, ceu patet ex", Isaiah. xlviii. 22. Gejerus.