For his eyes are upon the ways of man - None can escape from his notice; compare Psalm 139:2-3.

For his eyes are upon the ways of man,.... Which denotes the omniscience of God, which reaches to every man, to every individual, and to all men in general; and to their ways, to every step taken by them, to the whole of their lives and conversations, and every action of them; to all their internal and external ways and goings; perhaps the former may be meant in this, and the latter in the following clause. This may denote all their inward thoughts, the workings of their mind, the imaginations of their heart; all their secret purposes, designs, and schemes; and all the desires and affections of their soul; and all these, whether good or bad:
and he seeth all his goings; the whole of his walk and conversation, conduct and behaviour; all his external ways, works, and actions; and these whether of good or bad men, see Psalm 139:1.

God's omniscience and omnipotence enable Him to execute immediate justice. He needs not to be long on the "watch," as Job thought (Job 7:12; 2-Chronicles 16:9; Jeremiah 32:19).

21 For His eyes are upon the ways of each one,
And He seeth all his steps.
22 There is no darkness nor shadow of death
Wherein the workers of iniquity might hide themselves.
23 For He needeth not long to regard a man
That he may enter into judgment with God.
As the preceding strophe showed that God's creative order excludes all partiality, so this strophe shows that His omniscience qualifies Him to be an impartial judge. He sees everything, nothing can escape His gaze; He sees through man without being obliged to wait for the result of a judicial investigation. שׂים with על does not here signify: to lay upon (Saad., Gecat.), but as Job 37:15, and as with אל (Job 34:14) or בּ (Job 23:6); to direct one's attention (supply לבּו, Job 1:8) towards anything; the fut. has here a modal signification; עוד is used as e.g., Genesis 46:29 : again and again, continuously; and in the clause expressive of purpose it is אל־אל (instead of אליו, a very favourite combination used throughout the whole book, Job 5:8; Job 8:5; Job 13:3, and so on) from the human standpoint: He, the all-seeing One, needs not to observe him long that he should enter into judgment with God - He knows him thoroughly before any investigation takes place, which is not said without allusion to Job's vehement longing to be able to appear before God's tribunal.

For - God doth not destroy either prince or people unjustly, no nor out of his mere pleasure, but for their sins, which he sees exactly, although they use all possible arts to hide them.