The guide of her youth - Better, the familiar friend (compare Proverbs 16:28; Proverbs 17:9). The "friend" is, of course, the husband, or the man to whom the strange woman first belonged as a recognized concubine. Compare Jeremiah 3:4
The covenant of her God - The sin of the adulteress is not against man only but against the Law of God, against His covenant. The words point to some religious formula of espousals. Compare Malachi 2:14.

Which forsaketh the guide of her youth - Leaves her father's house and instructions, and abandons herself to the public.
The covenant of her God - Renounces the true religion, and mixes with idolaters; for among them prostitution was enormous. Or by the covenant may be meant the matrimonial contract, which is a covenant made in the presence of God between the contracting parties, in which they bind themselves to be faithful to each other.

Which forsaketh the (k) guide of her youth, and forgetteth the covenant of her God.
(k) That is, her husband, who is her head and guide to govern her, from whom she ought not to depart, but remain in his subjection.

Which forsaketh the guide of her youth,.... Not God, the God of her life, and who had provided for her from her youth up; nor her parent that had taken care of her in her infancy, and had been the guardian of her virgin state; but her husband, to whom she was married in her youth, and to whom she gave up herself to be guided and directed, ruled and governed, by: and as it is an aggravation of evil in a man to deal treacherously against the wife of his youth, and the wife of his covenant, Malachi 2:14; so it is in a woman to forsake "the friend" or "companion of her youth" (w), as the phrase may be rendered; who loved her and espoused her in his youthful age, and with whom he had lived long in love and friendship, and in great happiness, but now forsakes him; her affections being alienated from him, leaves his company and bed, and associates with others. Gersom interprets this of the human understanding, appointed to govern the other powers and faculties of the soul;
and forgetteth the covenant of her God: not the covenant made with Noah, in which adultery, as well as other things, were forbidden; nor the law of Moses, or covenant at Sinai, in which it was condemned; but the marriage covenant, which she entered into with her husband when espoused to him, and when they mutually obliged themselves to be faithful to one another: and this is called "the covenant of God"; not only because God is the author and institutor of marriage, and has directed and enjoined persons to enter into such a contract with one another; but because he is present at it, and is a witness of such an engagement, mid is appealed unto in it; which, as it adds to the solemnity of it, makes the violation of it the more criminal. So the church of Rome has forsook Christ, who was her guide in her first settlement, and her husband she professed to be espoused to, as a chaste virgin; and has followed other lovers, and become the mother of harlots; so false teachers leave their guide, the Scriptures, and bring in damnable heresies, and deny the Lord that bought them, 2-Peter 2:1.
(w) "amieum adolescentiae suae", De Dieu, Michaelis; "socium juventutis suae", Schultens.

guide . . . youth--lawful husband (Jeremiah 3:4).
covenant . . . God--of marriage made in God's name.

17 Who forsakes the companion of her youth,
And forgets the covenant of her God;
18 For she sinks down to death together with her house,
And to the shadow of Hades her paths -
19 All they who go to her return not again,
And reach not the paths of life
אלּוּף, as here used, has nothing to do with the phylarch-name, similar in sound, which is a denom. of אלף; but it comes immediately from אלף, to accustom oneself to a person or cause, to be familiar therewith (while the Aram. אלף, ילף, to learn, Pa. to teach), and thus means, as the synon. of רע, the companion or familiar associate (vid., Schultens). Parallels such as Jeremiah 3:4 suggested to the old interpreters the allegorical explanation of the adulteress as the personification of the apostasy or of heresy. Proverbs 2:18 the lxx translate: ἔθετο γὰρ παρὰ τῷ θανάτῳ τὸν οἶκον αὐτῆς: she (the dissolute wife) has placed her house beside death (the abyss of death). This שׁחה [ἔθετο] is perhaps the original, for the text as it lies before us is doubtful, though, rightly understood, admissible. The accentuation marks בּיתהּ as the subject, but בּית is elsewhere always masc., and does not, like the rarer ארח, Proverbs 2:15, admit in usage a double gender; also, if the fem. usage were here introduced (Bertheau, Hitzig), then the predicate, even though ביתה were regarded as fem., might be, in conformity with rule, שׁח, as e.g., Isaiah 2:17. שׁחה is, as in Psalm 44:26, 3rd pr. of שׁוּח, Arab. sâkh, to go down, to sink; the emendation שׁחה (Joseph Kimchi) does not recommend itself on this account, that שׁחה and שׁחח mean, according to usage, to stoop or to bend down; and to interpret (Ralbag, השׁפילה) שׁחה transitively is inadmissible. For that reason Aben Ezra interprets ביתה as in apposition: to death, to its house; but then the poet in that case should say אל־שׁאול, for death is not a house. On the other hand, we cannot perceive in ביתה an accus. of the nearer definition (J. H. Michaelis, Fl.); the expression would here, as 15a, be refined without purpose. Bttcher has recognised ביתה as permutative, the personal subject: for she sinks down to death, her house, i.e., she herself, together with all that belongs to her; cf. the permutative of the subject, Job 29:3; Isaiah 29:23 (vid., comm. l.c.), and the more particularly statement of the object, Exodus 2:6, etc. Regarding רפאים, shadows of the under-world (from רפה, synon. חלה, weakened, or to become powerless), a word common to the Solomonic writings, vid., Comment. on Isaiah, p. 206. What Proverbs 2:18 says of the person of the adulteress, Proverbs 2:19 says of those who live with her ביתה, her house-companions. בּאיה, "those entering in to her," is equivalent to בּאים אליה; the participle of verbs eundi et veniendi takes the accusative object of the finite as gen. in st. constr., as e.g., Proverbs 1:12; Proverbs 2:7; Genesis 23:18; Genesis 9:10 (cf. Jeremiah 10:20). The ישׁוּבוּן, with the tone on the ult., is a protestation: there is no return for those who practise fornication,
(Note: One is here reminded of the expression in the Aeneid, vi. 127-129:
Revocare gradum superasque evadere ad auras,
Hoc opes, hoc labor est.
See also an impure but dreadful Talmudic story about a dissolute Rabbi, b. Aboda zara, 17a.)
and they do not reach the paths of life from which they have so widely strayed.
(Note: In correct texts ולא־ישיגו has the Makkeph. Vid., Torath Emeth, p. 41; Accentuationssystem, xx. 2.)

Forsaketh - Her husband whom she took to be her guide and governor, in her youth. The covenant - The marriage covenant: so called because God is the author of that mutual obligation: and because God is called to be the witness and judge of that solemn promise and covenant.