Biblical Commentary on the Old Testament, by Carl Friedrich Keil and Franz Delitzsh, [1857-78], at sacred-texts.com
This is the "prince's Psalm,"
(Note: Eyring, in his Vita of Ernest the Pious Duke of Saxe-Gotha, v. 1601, d. 1675, relates that he sent an unfaithful minister a copy of the 101st Psalm, and that it became a proverb in the country, when an official had done anything wrong: He will certainty soon receive the prince's Psalm to read.)
or as it is inscribed in Luther's version, "David's mirror of a monarch." Can there be any more appropriate motto for it than what is said of Jahve's government in Psa 99:4? In respect of this passage of Psa 99:1-9, to which Psa 100:1-5 is the finale, Psa 101:1-8 seems to be appended as an echo out of the heart of David. The appropriateness of the words לדוד מזמור (the position of the words is as in Psa 24:1-10; 40; 109:1-110:7; 139) is corroborated by the form and contents. Probably the great historical work from which the chronicler has taken excerpts furnished the post-exilic collector with a further gleaning of Davidic songs, or at least songs that were ascribed to David. The Psalm before us belongs to the time during which the Ark was in the house of Obed-Edom, where David had left it behind through terror at the misfortune of Uzzah. David said at that time: "How shall the Ark of Jahve come to me (the unholy one)?" Sa2 6:8. He did not venture to bring the Ark of the Fearful and Holy One within the range of his own house. In our Psalm, however, he gives utterance to his determination as king to give earnest heed to the sanctity of his walk, of his rule, and of his house; and this resolve he brings before Jahve as a vow, to whom, in regard to the rich blessing which the Ark of God diffuses around it (Sa2 6:11.), he longingly sighs: "When wilt Thou come to me?!" This contemporaneous reference has been recognised by Hammond and Venema. From the fact that Jahve comes to David, Jerusalem becomes "the city of Jahve," Psa 101:8; and to defend the holiness of this the city of His habitation in all faithfulness, and with all his might, is the thing to which David here pledges himself.
The contents of the first verse refer not merely to the Psalm that follows as an announcement of its theme, but to David's whole life: graciousness and right, the self-manifestations united ideally and, for the king who governs His people, typically in Jahve, shall be the subject of his song. Jahve, the primal source of graciousness and of right, it shall be, to whom he consecrates his poetic talent, as also his playing upon the harp. חסד is condescension which flows from the principle of free love, and משׁפּט legality which binds itself impartially and uncapriciously to the rule (norm) of that which is right and good. They are two modes of conduct, mutually tempering each other, which God requires of every man (Mic 6:8, cf. Mat 23:23 : τὴν κρίσιν καὶ τὸν ἔλεον), and more especially of a king. Further, he has resolved to give heed, thoughtfully and with an endeavour to pursue it (השׂכּיל בּ as in Dan 9:13), unto the way of that which is perfect, i.e., blameless. What is further said might now be rendered as a relative clause: when Thou comest to me. But not until then?! Hitzig renders it differently: I will take up the lot of the just when it comes to me, i.e., as often as it is brought to my knowledge. But if this had been the meaning, בּדבר would have been said instead of בּדרך (Exo 18:16, Exo 18:19; Sa2 19:12 ); for, according to both its parts, the expression דוך תמים is an ethical notion, and is therefore not used in a different sense from that in Psa 101:6. Moreover, the relative use of the interrogative מתי in Hebrew cannot be supported, with the exception, perhaps, of Pro 23:35. Athanasius correctly interprets: ποθῶ σου τὴν παρουσίαν, ὦ δέσποτα, ἱμείρομαί σου τῆς ἐπιφανείας, ἀλλὰ δὸς τὸ ποθούμενον. It is a question of strong yearning: when wilt Thou come to me? is the time near at hand when Thou wilt erect Thy throne near to me? If his longing should be fulfilled, David is resolved to, and will then, behave himself as he further sets forth in the vows he makes. He pledges himself to walk within his house, i.e., his palace, in the innocence or simplicity of his heart (Psa 78:72; Pro 20:7), without allowing himself to be led away from this frame of mind which has become his through grace. He will not set before his eyes, viz., as a proposition or purpose (Deu 15:9; Exo 10:10; Sa1 29:10, lxx), any morally worthless or vile matter whatsoever (Psa 41:8, cf. concerning בליּעל, Psa 18:5). The commission of excesses he hates: עשׂה is infin. constr. instead of עשׂות as in Gen 31:28; Gen 50:20; Pro 21:3, cf. ראה Gen 48:11, שׁתו Pro 31:4. סטים (like שׂטים in Hos 5:2), as the object of עשׂה, has not a personal (Kimchi, Ewald) signification (cf. on the other hand Psa 40:5), but material signification: (facta) declinantia (like זדים, Psa 19:13, insolentia; הבלים, Zac 11:7, vincientia); all temptations and incitements of this sort he shakes off from himself, so that nothing of the kind cleaves to him. The confessions in Psa 101:4 refer to his own inward nature: לב עקּשׁ (not עקּשׁ־לב, Pro 17:20), a false heart that is not faithful in its intentions either to God or to men, shall remain far from him; wickedness (רע as in Psa 36:5) he does not wish to know, i.e., does not wish to foster and nurture within him. Whoso secretly slanders his neighbour, him will he destroy; it will therefore be so little possible for any to curry favour with him by uncharitable perfidious tale-bearing, of the wiliness of which David himself had had abundant experience in his relation to Saul, that it will rather call forth his anger upon him (Pro 30:10). Instead of the regularly pointed מלושׁני the Ker reads מלשׁני, melŏshnı̂, a Poel (לשׁן linguâ petere, like עין oculo petere, elsewhere הלשׁין, Pro 30:10) with ŏ instead of ō (vid., on Psa 109:10; Psa 62:4) and with Chirek compaginis (vid., on Psa 113:1-9). The "lofty of eyes," i.e., supercilious, haughty, and the "broad of heart," i.e., boastful, puffed up, self-conceited (Pro 28:25, cf. Psa 21:4), him he cannot endure (אוּכל, properly fut. Hoph., I am incapable of, viz., לשׂאת, which is to be supplied as in Isa 1:13, after Pro 30:21; Jer 44:22).
(Note: In both instances the Masora writes אותו (plene), but the Talmud, B. Erachin 15b, had אתו before it when it says: "Of the slanderer God says: I and he cannot dwell together in the world, I cannot bear it any longer with him (אתּו).")
On the other hand, his eyes rest upon the faithful of the land, with the view, viz., of drawing them into his vicinity. Whoso walks in the way of uprightness, he shall serve him (שׁרת, θεραπεύειν, akin to עבד, δουλεύειν). He who practises deceit shall not stay within his house; he who speaks lies shall have no continuance (יכּון is more than equivalent to נכון) before (under) his eyes. Every morning (לבּקרים as in Psa 73:14; Isa 33:2; Lam 3:23, and לבקרים, Job 7:18), when Jahve shall have taken up His abode in Jerusalem, will he destroy all evil-doers (רשׁעי as in Psa 119:119), i.e., incorrigibly wicked ones, wherever he may meet them upon the earth, in order that all workers of evil may be rooted out of the royal city, which is now become the city of Jahve.