Surely he scorneth the scorners; literally, if with regard to the scorners he scorneth (im lalletsim hu yalits); i.e. he repays scorn with scorn; or, as Rabbi Salomon, "He renders to them so that they fall in their own derision (reddit ipsis ut in sua derisione corruant)."
He renders their schemes abortive. He resists them. The scorners (letsim) are those who treat with scoffing regard the precepts and truths of God; the arrogant, proud, insolent, here placed in contrast with "the lowly."
Vulgate, derisores; LXX; ὐπερήφανοι, "the overbearing." The לְ for (l'ha), prefixed to letsim, signifies "with regard to," as in Job 32:4 (cf. Psalms 16:3, "With regard to the saints (lik'ddshim), in them only I delight").
But he giveth grace unto the lowly; or, on the other hand, the לְה prefixed to laanayim, "to the lowly," having that antithetical force here as in Job 8:20. The lowly (anayyim); Vulgate, mansueti; LXX; ταπωῖνοι; properly, "the afflicted," with added notion of submission and lowly demeanour, and hence the meek, gentle—the gentle towards man, and the abased and lowly before God.
St. James (James 4:6) quotes the LXX. of this passage, "God resisteth the proud, but giveth grace to the humble." With the exception of substituting κύριος for θεός (cf. 1 Peter 5:5), our Lord's parable of the Pharisee and publican illustrates the teaching of this verse (Luke 18:9-14).