Good as it is to "handle a matter wisely," it is far better to "trust in the Lord." The former is really impossible except through the latter.

He that handleth a matter wisely shall find good,.... That frames and composes his discourse well on any subject he takes in hand; or manages his affairs prudently and discreetly, in which he is concerned; or that wisely attends to the affair of humility, as Aben Ezra: or rather to the word, that is, to the word of God; is not a careless, negligent, unconcerned hearer of the word, but a diligent and attentive one; whose heart is opened by the Spirit of God to attend to what is spoken in it; who lays it up in his heart, and makes it the rule of his conduct in life: such a man finds good things; things which are for his profit, edification, and instruction; good truths, good doctrines, good counsel and advice, good directions and instructions; promises of good things, things for his present comfort and future happiness;
and whoso trusteth in the Lord, happy is he; not to his own wisdom; nor in his own strength; nor in his riches, nor righteousness; nor in the favour of men, no, not of princes; but in the Lord, and in his Word; he shall want no good thing, he is kept in perfect peace; he is in the utmost safety, is like Mount Zion, that can never be removed, Jeremiah 17:7.

handleth a matter--wisely considers "the word," that is, of God (compare Proverbs 13:13).
trusteth--(Compare Psalm 2:12; Psalm 118:8-9).

20 He that giveth heed to the word will find prosperity;
And he that trusteth in Jahve, blessed is he!
The "word" here is the word κατ ̓ ἐξ., the divine word, for משׂכּיל על־דּבר is the contrast of בּז לדבר, Proverbs 13:13, cf. Nehemiah 8:13. טוב is meant, as in Proverbs 17:20, cf. Proverbs 13:21, Psalm 23:6; to give heed to God's word is the way to true prosperity. But at last all depends on this, that one stand in personal fellowship with God by means of faith, which here, as at Proverbs 28:25; Proverbs 29:25, is designated after its specific mark as fiducia. The Mashal conclusion אשׁריו occurs, besides here, only at Proverbs 14:21; Proverbs 29:18.

Good - He who orders his affairs with discretion.