Some prefer the margin, and render, words of pleasantness are pure. Gracious words are to God as a pure acceptable offering, the similitude being taken from the Levitical ritual, and the word "pure" in half ceremonial sense (compare Malachi 1:11).

The thoughts of the wicked [are] an abomination to the LORD: but [the words] of the pure [are] (h) pleasant words.
(h) That is, wholesome and profitable to the hearers.

The thoughts of the wicked are an abomination to the Lord,.... They are known unto the Lord, who is the searcher of the heart, and a discerner of the thoughts and intents of it; he knows they are vain and sinful, yea, that they are only evil, and that continually, and therefore are hateful and abominable to him; it may be rendered "the thoughts of evil", as by the Targum; or evil thoughts, as the Septuagint, Vulgate Latin, and the Oriental versions; but Aben Ezra interprets as we, the thoughts of a wicked man, which are never otherwise but evil; whereas in a good man, though there are many evil thoughts which are abominable to himself, yet there are some good thoughts, and which are pleasing to the Lord, as follows;
but the words of the pure are pleasant words; that is, unto the Lord; which are the same with their thoughts, and are the effect of them, and so stand opposed to the thoughts of the wicked; these, expressed either in a way of prayer or of praise, are sweet and pleasant, and acceptable unto God through Christ; as likewise their words and discourse in religious conversation, which also minister grace unto the hearer, and are very delightful and pleasing to saints; the words may be supplied thus, "but the thoughts of the pure", of such who are pure in heart, whose hearts are purified by faith in the blood of Christ, are "words of pleasantness", so Gersom; there is a language in thought which is known to a man's self, and by the Lord; there is the meditation or discourse of the heart, and this being about divine and spiritual things is pleasing to God; he hearkens to it, and writes a book of remembrance for them that fear him, and have thought on his name; see Psalm 19:14.

The thoughts of wicked men offend Him who knows the heart.

are pleasant words--that is, pleasing to God (Proverbs 8:8-9).

26 An abomination to Jahve are evil thoughts;
But gracious words are to Him pure.
Not personally (Luther: the plans of the wicked) but neutrally is רע here meant as at Proverbs 2:14, and in אושׁת רע, Proverbs 6:24 (cf. Pers. merdi nı̂ku, man of good = good man), vid., Friedr. Philippi's Status Constr. p. 121. Thoughts which are of a bad kind and of a bad tendency, particularly (what the parallel member brings near) of a bad disposition and design against others, are an abomination to God; but, on the contrary, pure, viz., in His eyes, which cannot look upon iniquity (Habakkuk 1:13), are the אמרי־נעם, words of compassion and of friendship toward men, which are (after 26a) the expression of such thoughts, thus sincere, benevolent words, the influence of which on the soul and body of him to whom they refer is described, Proverbs 16:24. The Syr., Targ., Symmachus, Theodotion, and the Venet. recognise in וּטהורים the pred., while, on the contrary, the lxx, Jerome, and Luther (who finally decided for the translation, "but the pure speak comfortably") regard it as subject. But that would be an attribution which exceeds the measure of possibility, and for which אמרים or דברי must be used; also the parallelism requires that טהורים correspond with 'תועבת ה. Hence also the reference of וטהורים to the judgment of God, which is determined after the motive of pure untainted law; that which proceeds from such, that and that only, is pure, pure in His sight, and thus also pure in itself.

Pleasant - Acceptable to God.