Whoso is simple - Let the young, heedless, and giddy attend to my teaching.
Him that wanteth understanding - Literally, he that wanteth a heart; who is without couraye, is feeble and fickle, and easily drawn aside from the holy commandment.

Whoever [is] (e) simple, let him turn in here: [as for] him that lacketh understanding, she saith to him,
(e) He who knows his own ignorance, and is void of malice.

Whoso is simple, let him turn in hither,.... Into Wisdom's house, so well built and furnished; the church of Christ, as a house of instruction; a school, where such who are "simple", weak, and foolish, may learn. Here are many instructors; saints instruct one another; ministers of the word are teachers; yea, Father, Son, and Spirit, here teach and instruct, and none teach like them. Here many lessons are to be learned concerning themselves, concerning Christ, and concerning their duty to God and men; all sorts of persons may learn here, such who know ever so much or ever so little. Or let him turn in here, as into an inn, into which passengers or travellers turn for accommodations; see Proverbs 9:15. The saints are travellers here, at a distance from their Father's house, and need refreshment by the way; the church of God is an inn of good accommodations; here is room enough to entertain them; here are good lodgings for rest and safety, and good provisions, and all of free cost. And now these are the words of Wisdom, or Christ, either in person, or by his maidens, his ministers, inviting such who are "simple" to turn in hither, and partake of the provisions in it; that is, not such who are quite stupid and insensible, sottish, incorrigible, and irreclaimable; but who are sensible of their folly and simplicity; who are but of weak capacities, apt to be credulous, and so easily imposed upon and deceived;
as for him that wanteth understanding; not the natural faculty of the understanding, nor an understanding of things natural and civil; but of things spiritual and evangelical, as of the grace of God; of salvation by Christ; of the work of the Spirit; of themselves and their state; of the Gospel, and the mysteries of it; and who are sensible of their ignorance and want of understanding; which is the first thing the Spirit of God convinces men of; or who are so in comparison of others, are weak in knowledge and experience. Now these Christ does not despise, but invites them into his house for instruction; and where can they be better? and who so fit and proper to be here, and be with Wisdom, than such as these?
she saith to him: as follows.

(Compare Proverbs 1:4; Proverbs 6:32). Wisdom not only supplies right but forbids wrong principles.

Now follows the street-sermon of Wisdom inviting to her banquet:
4 Who is simple? let him come hither!"
Whoso wanteth understanding, to him she saith:
5 "Come, eat of my bread,
And drink of the wine which I have mingled!
6 Cease, ye simple, and live,
And walk straight on in the way of understanding."
The question מי פּתי (thus with Munach, not with Makkeph, it is to be written here and at Proverbs 9:16; vid., Baer's Torath Emeth, p. 40), quis est imperitus, is, as Psalm 25:12, only a more animated expression for quisquis est. The retiring into the background of the נערות (servants), and the immediate appearance of Wisdom herself, together with the interruption, as was to be expected, of her connected discourses by the אמרה לּו, are signs that the pure execution of the allegorical representation is her at an end. Hitzig seeks, by the rejection of Proverbs 9:4, Proverbs 9:5, Proverbs 9:7-10, to bring in a logical sequence; but these interpolations which he cuts out are yet far more inconceivable than the proverbial discourses in the mouth of Wisdom, abandoning the figure of a banquet, which besides are wholly in the spirit of the author of this book. That Folly invites to her, Proverbs 9:16, in the same words as are used by Wisdom, Proverbs 9:4, is not strange; both address themselves to the simple (vid., on פּתי at Proverbs 1:4) and those devoid of understanding (as the youth, Proverbs 7:7), and seek to bring to their side those who are accessible to evil as to good, and do not dully distinguish between them, which the emulating devertat huc of both imports. The fourth verse points partly backwards, and partly forwards; 4a has its introduction in the תקרא of Proverbs 9:3; on the contrary, 4b is itself the introduction of what follows. The setting forth of the nom. absolutus חסר־לב is conditioned by the form of 4a; the מי (cf. 4a) is continued (in 4b) without its needing to be supplied: excors (= si quis est excors) dicit ei (not dixit, because syntactically subordinating itself to the תקרא). It is a nominal clause, whose virtual predicate (the devoid of understanding is thus and thus addressed by her) as in Proverbs 9:16.

Simple - Ignorant, and weak.