We are blind to our own faults, do not see ourselves as others see us. There is One who tries not the "ways" only, but the "spirits" Hebrews 4:12 : this is the true remedy against self-deceit.

All the ways of a man are clean in his own eyes,.... All right and well, not only some, but all, having a high opinion of himself; for this is to be understood of a self-righteous man, who is pure in his own eyes, though not cleansed from his filthiness, and so fancies every way he walks in, and everything he does, is pure; this is owing to want of knowledge of the impurity of his nature; was he sensible of this, he would see that his best righteousness is as filthy rags and to his ignorance of the spirituality of the law, which, was he acquainted with, he would find, on comparing himself with it, that he and all he did was polluted and unclean: some read the words, "all the ways of a pure man are before his eyes": the eyes of the Lord, he sees them, and approves of them; so Aben Ezra; and to this agrees the Septuagint version, "all the works of an humble man are manifest with God"; and the Arabic version, "all the works of an humble man are clean before God"; but the former reading and sense seem best;

but the Lord weigheth the spirits; searches and tries the hearts; he sees, knows, and observes the principles of all actions, and can as exactly adjust the nature and quality of them, as a man, with a pair of scales in his hands, can tell precisely the weight of anything put into them; the Lord weighs the spirits, or hearts, from whence all actions flow, by his omniscience, and accordingly judges of them by that, and not by the outward appearance; and he weighs all actions by his law, in the balance of the sanctuary, where they are found wanting, and come greatly short of that purity and perfection pharisaical persons imagine there is in them.

2 Every way of a man is pure in his own eyes;

   But a weigher of the spirits is Jahve.

Variations of this verse are Proverbs 21:2, where ישׁר for זך (according to the root-meaning: pricking in the eyes, i.e., shining clear, then: without spot, pure, vid., Fleischer in Levy's Chald. Wrterbuch, i. 424), לבּות for רוּחות, and כּל־דּרך for כּל־דּרכי, whereupon here without synallage (for כל means the totality), the singular of the pred. follows, as Isaiah 64:10; Ezekiel 31:15. For the rest, cf. with 2a, Proverbs 14:12, where, instead of the subj. בּעיני, is used לפני, and with 2b, Proverbs 24:12, where God is described by תּכן לבּות. The verb תּכן is a secondary formation from כּוּן (vid., Hupfeld on Psalm 5:7), like תּכן from Arab. tyaḳn (to be fast, sure), the former through the medium of the reflex. התכּונן, the latter of the reflex. Arab. âitḳn; תּכן means to regulate (from regula, a rule), to measure off, to weigh, here not to bring into a condition right according to rule (Theodotion, ἑδράζων, stabiliens, Syr. Targ. מתקּן, Venet. καταρτίζει; Luther, "but the Lord maketh the heart sure"), but to measure or weigh, and therefore to estimate rightly, to know accurately (Jerome, spiritum ponderator est Dominus). The judgment of a man regarding the cause of life, which it is good for him to enter upon, lies exposed to great and subtle self-deception; but God has the measure and weight, i.e., the means of proving, so as to value the spirits according to their true moral worth; his investigation goes to the root (cf. κριτικός, Hebrews 4:12), his judgment rests on the knowledge of the true state of the matter, and excludes all deception, so that thus a man can escape the danger of delusion by no other means than by placing his way, i.e., his external and internal life, in the light of the word of God, and desiring for himself the all-penetrating test of the Searcher of hearts (Psalm 139:23.), and the self-knowledge corresponding to the result of this test.

All the ways of a man are {b} clean in his own eyes; but the LORD weigheth the spirits.

(b) He shows by it that man flatters himself in his doings, calling that virtue, which God terms vice.

16:2 Weigheth - Exactly knows as men do the things which they weigh. Spirits - The hearts of men.

2. clean-or, "faultless."

weigheth-or, "tries," "judges," implying that they are faulty (Pr 21:2; 24:12).

16:1 The renewing grace of God alone prepares the heart for every good work. This teaches us that we are not sufficient of ourselves to think or speak any thing wise and good. 2. Ignorance, pride, and self-flattery render us partial judges respecting our own conduct. 3. Roll the burden of thy care upon God, and leave it with him, by faith and dependence on him.