They assure themselves in an evil work. He proceeds to complain of the perverse determination with which they pursued their wickedness, and of their combinations amongst themselves; remarking, at the same time, upon the confidence with which they stirred one another up to the most daring acts of iniquity. In this there can be little doubt that they were encouraged by the present state of weakness to which David was reduced in his circumstances, taking occasion, when they found him in poverty and exile, and without means of resistance, to persecute him with the greater freedom. Having adverted to them as being beyond hope of amendment, and incapable of any impressions of humanity, he speaks of their meeting together to plot his destruction; and, in connection with this, of the unbounded confidence which they were led to display, from a belief that their designs were not seen. It is well known that one circumstance which strengthens the false security of the wicked, and encourages them to triumph in their crafty policy towards the simple and upright in heart, is their thinking that they can cover their crimes by such pretexts as they have always at hand. They say, Who shall see them? The word lmv, lamo, them, may refer either to the workers of iniquity themselves, or to the snares spoken of in the preceding clause. The first seems the preferable meaning. They run recklessly, and without restraint, in the ways of sin, blinded by their pride, and influenced neither by the fear of God nor a sense of shame. In the verse which follows, he animadverts severely upon the deceit which they practiced. He speaks of their having exhausted all the arts of mischief, so as to have left nothing in this department to be discovered. The search referred to has relation to the secret methods of doing evil. He adds, that their malice was deep. By the inward part and the heart, which was deep, he means the hidden devices to which the wicked have recourse for concealment. Some, instead of translating the words, the inward part of each, etc., give a more indefinite sense to 'ys, ish, and read, the inward part, and deep heart, of every one, is found in them; that is, his enemies contrived to comprise in themselves all that men have ever displayed in the shape of craft and subtilty. Either rendering may be adopted; for it is evidently David's meaning that his enemies practiced secret stratagem as well as open violence, to compass his ruin, and showed themselves to be possessed of the deepest penetration in discovering dark and unimagined methods of doing mischief.

They encourage themselves - literally, they strengthen themselves, or make themselves strong. That is, they take counsel; they encourage each other; they urge one another forward; they suggest to each other methods by which what they purpose may be done, and by which difficulties may be overcome. This was a part of their "secret counsel" or their consultation, Psalm 64:2.
In an evil matter - Margin, as in Hebrew, speech. The reference is to their purpose or plan. They strengthen themselves for doing what they know to be a wrong or wicked thing.
They commune - literally, they tell or speak. That is, they tell each other how it may be done, or suggest different methods by which it may be successfully accomplishled. They compare views, that they may select that which will be most likely to be successful. All this indicates plan, consultation, design.
Of laying snares privily - Margin, as in Hebrew, to hide snares. This is a figure derived from the method of taking wild beasts. See Psalm 7:15, note; Psalm 38:12, note. The reference here is to some secret plan by which they intended that the author of the psalm should be entrapped and ruined. It was not a plan of open and manly warfare, but a purpose to destroy him when he would have no opportunity of defense.
They say, Who shall see them? - That is, who will see the snares or pit-falls? Who will be aware of their existence? They sought to make the plan so secret that no one could discover it, or even suspect it; to keep it so concealed that he for whom it was intended could not be put on his guard. Compare Psalm 10:8-9.

They commune of laying snares - They lay snares to entrap those whom they cannot slay by open attack or private ambush.

They (f) encourage themselves [in] an evil matter: they commune of laying snares privily; they say, Who shall see them?
(f) The more the wicked set God's children in misery, the more bold and impudent are they in oppressing them.

They encourage themselves in an evil matter,.... Or "strengthen him" (c); that is, Saul, by making use of arguments and reasonings to induce him to go on in his wicked persecution of David; or they strengthened and hardened themselves in their wickedness, as Saul's courtiers and the enemies of Christ did, and as all wicked men do, when they observe the sentence against them is not speedily executed, Ecclesiastes 8:11;
they commune of laying snares privily; that is, they conversed together, and consulted how to lay snares for the perfect man in the most private manner, that they might entrap him and destroy him;
they say, who shall see them? either the snares laid, or the persons that laid them? None; no, not even God himself; see Psalm 10:11.
(c) "firmant illi", Muis.

A sentiment here more fully presented, by depicting their deliberate malice.

The evil speech is one with the bitter speech in Psalm 64:4, the arrow which they are anxious to let fly. This evil speech, here agreement or convention, they make firm to themselves (sibi), by securing, in every possible way, its effective execution. ספּר (frequently used of the cutting language of the ungodly, Psalm 59:13; Psalm 69:27; cf. Talmudic ספּר לשׁון שׁלישׁי, to speak as with three tongues, i.e., slanderously) is here construed with ל of that at which their haughty and insolent utterances aim. In connection therewith they take no heed of God, the all-seeing One: they say (ask), quis conspiciat ipsis. There is no need to take למו as being for לו (Hitzig); nor is it the dative of the object instead of the accusative, but it is an ethical dative: who will see or look to them, i.e., exerting any sort of influence upon them? The form of the question is not the direct (Psalm 59:8), but the indirect, in which מי, seq. fut., is used in a simply future (Jeremiah 44:28) or potential sense (Job 22:17; 1-Kings 1:20). Concerning עולת, vid., Psalm 58:3. It is doubtful whether תּמּנוּ
(Note: תּמּנוּ in Baer's Psalterium is an error that has been carried over from Heidenheim's.)
is the first person (= תּמּונוּ) as in Numbers 17:13, Jeremiah 44:18, or the third person as in Lamentations 3:22 (= תּמּוּ, which first of all resolved is תּנמוּ, and then transposed תּמּנוּ, like מעזניה = מענזיה = מעזּיה, Isaiah 23:11). The reading טמנוּ, from which Rashi proceeds, and which Luther follows in his translation, is opposed by the lxx and Targum; it does not suit the governing subject, and is nothing but an involuntary lightening of the difficulty. If we take into consideration, that תּמם signifies not to make ready, but to be ready, and that consequently חפשׂ מחפּשׂ is to be taken by itself, then it must be rendered either: they excogitate knavish tricks or villainies, "we are ready, a clever stroke is concocted, and the inward part of man and the heart is deep!" or, which we prefer, since there is nothing to indicate the introduction of any soliloquy: they excogitate knavish tricks, they are ready - a delicately devised, clever stroke (nominative of the result), and (as the poet ironically adds) the inward part of man and the heart is (verily) deep. There is nothing very surprising in the form תּמּנוּ for תּמּוּ, since the Psalm, whenever they depict the sinful designs and doings of the ungodly, delight in singularities of language. On ולב (not ולב) = (אישׁ) ולב = ולבּו, cf. Psalm 118:14.