The proverbs in Proverbs 16:1-7 have, more than any other group, an especially religious character impressed upon them. The name of Yahweh as Giver, Guide, Ruler, or Judge, meets us in each of them.

Better, The plans of the heart belong to man, but the utterance of the tongue is from Yahweh. Thoughts come and go, as it were, spontaneously; but true, well ordered speech is the gift of God. Compare Proverbs 16:9.

The preparations of the heart in man - The Hebrew is לאדם מערכי לב leadam maarchey leb, which is, literally, "To man are the dispositions of the heart; but from the Lord is the answer of the tongue." Man proposes his wishes; but God answers as he thinks proper. The former is the free offspring of the heart of man; the latter, the free volition of God. Man may think as he pleases, and ask as he lists; but God will give, or not give, as he thinks proper. This I believe to be the meaning of this shamefully tortured passage, so often vexed by critics, their doubts, and indecisions. God help them! for they seldom have the faculty of making any subject plainer! The text does not say that the "preparations," rather dispositions or arrangements, מערכי maarchey "of the heart," as well as "the answer of the tongue, is from the Lord;" though it is generally understood so; but it states that the dispositions or schemes of the heart (are) man's; but the answer of the tongue (is) the Lord's. And so the principal versions have understood it.
Hominis est animam preparare; et Domini gubernare linguam - Vulgate. "It is the part of man to prepare his soul: it is the prerogative of the Lord to govern the tongue."
מן בר נש תרעיתא דלבא ומן יי ממללא דלישנא min bar nash taritha delibba; umin yeya mamlala delishana - Chaldee. "From the son of man is the counsel of the heart; and from the Lord is the word of the tongue."
The Syriac is the same. καρδια ανδρος λογζεσθω δικαια, Ἱνα ὑπο του θεου διορθωθῃ τα διαβηματα αυτῃ - Septuagint. "The heart of man deviseth righteous things, that its goings may be directed by God."
The Arabic takes great latitude: "All the works of an humble man are clean before the Lord; and the wicked shall perish in an evil day." Of a man fit to maken redy the inwitt: and of the Lorde to governe the tunge. - Old MS. Bible.
"A man maye well purpose a thinge in his harte: but the answere of the tonge cometh of the Lorde. - Coverdale.
Matthew's Bible, 1549, and Becke's Bible of the same date, and Cardmarden's of 1566, follow Coverdale. The Bible printed by R. Barker, at Cambridge, 4th., 1615, commonly called the Breeches Bible, reads the text thus: - "The preparations of the hart are in man; but the answere of the tongue is of the Lord." So that it appears that our first, and all our ancient versions, understood the text in the same way; and this, independently of critical torture, is the genuine meaning of the Hebrew text. That very valuable version published in Italian, at Geneva, fol. 1562, translates thus: Le dispositioni del cuore sono de l'huomo, ma la risposta del la lingua e dal Signore. "The dispositions of the heart are of man; but the answer of the tongue is from the Lord."
The modern European versions, as far as I have seen, are the same. And when the word dispositions, arrangements, schemes, is understood to be the proper meaning of the Hebrew term, as shown above, the sense is perfectly sound; for there may be a thousand schemes and arrangements made in the heart of man which he may earnestly wish God to bring to full effect, that are neither for his good nor God's glory; and therefore it is his interest that God has the answer in his own power. At the same time, there is no intimation here that man can prepare his own heart to wait upon, or pray unto the Lord; or that from the human heart any thing good can come, without Divine influence; but simply that he may have many schemes and projects which he may beg God to accomplish, that are not of God, but from himself. Hence our own proverb: "Man proposes, but God disposes." I have entered the more particularly into the consideration of this text, because some are very strenuous in the support of our vicious reading, from a supposition that the other defends the heterodox opinion of man's sufficiency to think any thing as of himself. But while they deserve due credit for their orthodox caution, they will see that no such imputation can fairly lie against the plain grammatical translation of the Hebrew text.

The (a) preparations of the heart belong to man, and the answer of the tongue, [are] from the LORD.
(a) He derides the presumption of man, who dares to attribute anything to himself, as to prepare his heart or such like, seeing that he is not able to speak a word unless God gives it to him.

The preparations of the heart in man,.... The sense of these words, according to our version, depends upon the next clause, and the meaning of the whole is, that a man can neither think nor speak without God: the "orderings" or "marshallings of the heart" (a), as it may be rendered; that is, of the thoughts of the heart, which are generally irregular and confused; the ranging them in order, as an army in battle array, or as things regularly placed on a well furnished table; the fixing them on any particular subject, though about things civil and natural, so as closely to attend to them, and proceed in a regular manner in the consideration of them, are not without the concurrence of divine Providence: and whereas the thoughts of men's hearts are evil, and that continually, and nothing but evil thoughts naturally proceed from thence; the ordering and marshalling of them, and fixing them to the attention and consideration of divine and spiritual things, are not without the supernatural grace of God; for we cannot think a good thought of ourselves, nor indeed anything of ourselves in a spiritual manner, 2-Corinthians 3:5; all preparations for religious service and duty, whether it be to pray unto God, or to preach in his name, are from the Lord; it is he that works in men both "to will and to do"; that gives them the willing mind, or a suitable frame for service, as well as ability to perform it; that pours out the Spirit of grace and supplication on them, and disposes and directs their minds to proper petitions, and furnishes his ministering servants in their studies with agreeable matter for their ministrations, Psalm 10:17;
and the answer of the tongue is from the Lord; who made man's mouth, and teaches him what to say, both before God and man; what he shall say in prayer to him, or in preaching to others; for the "door of utterance" in either service is from him, as well as the preparation for it: most versions and interpreters make these clauses distinct, the one as belonging to men, the other to God; thus, "to men belong the preparations of the heart, but from the Lord is the answer" or "speech of the tongue"; the former is said by way of concession, and according to the opinion of men; and the sense may be, be it so, that man has the marshalling and ordering of his own thoughts, and that he can lay things together in his mind, and think pertinently and properly on a subject, and is capable of preparing matter for a discourse; yet it is as easy to observe, that men can better form ideas of things in their minds, the they can express their sense and meaning; and though they may be ever so well prepared to speak, yet they are not able to do it, unless the Lord gives them utterance, and assists their memories; they lose what they had prepared, or deliver it in a disorderly and confused manner, and sometimes think to say one thing, and say another; their tongues are overruled by the Lord to say what they never intended, as in the cases of Balaam and Caiaphas. The Targum is,
"from man is the counsel of the heart, and from the Lord is the speech of the tongue.''
(a) "dispositiones sive ordinationes", Montanus, Munster, Vatablus, Piscator, Cocceius, Michaelis; "instructiones adversae aciei in corde", Schultens.

The renewing grace of God alone prepares the heart for every good work. This teaches us that we are not sufficient of ourselves to think or speak any thing wise and good.

(Proverbs. 16:1-33)
preparations--schemes.
in man--or literally, "to man," belonging, or pertaining to him.
the answer . . . Lord--The efficient ordering is from God: "Man proposes; God disposes."

Four proverbs of God, the disposer of all things:
1 Man's are the counsels of the heart;
But the answer of the tongue cometh from Jahve.
Gesen., Ewald, and Bertheau incorrectly understand 1b of hearing, i.e., of a favourable response to what the tongue wishes; 1a speaks not of wishes, and the gen. after מענה (answer) is, as at Proverbs 15:23; Micah 3:7, and also here, by virtue of the parallelism, the gen. subjecti Proverbs 15:23 leads to the right sense, according to which a good answer is joy to him to whom it refers: it does not always happen to one to find the fitting and effective expression for that which he has in his mind; it is, as this cog. proverb expresses it, a gift from above (δοθήσεται, Matthew 10:19). But now, since מענה neither means answering, nor yet in general an expression (Euchel) or report (Lwenstein), and the meaning of the word at 4a is not here in question, one has to think of him whom the proverb has in view as one who has to give a reason, to give information, or generally - since ענה, like ἀμείβεσθαι, is not confined to the interchange of words - to solve a problem, and that such an one as requires reflection. The scheme (project, premeditation) which he in his heart contrives, is here described as מערכי־לב, from ערך, to arrange, to place together, metaphorically of the reflection, i.e., the consideration analyzing and putting a matter in order. These reflections, seeking at one time in one direction, and at another in another, the solution of the question, the unfolding of the problem, are the business of men; but the answer which finally the tongue gives, and which here, in conformity with the pregnant sense of מענה (vid., at Proverbs 15:23, Proverbs 15:28), will be regarded as right, appropriate, effective, thus generally the satisfying reply to the demand placed before him, is from God. It is a matter of experience which the preacher, the public speaker, the author, and every man to whom his calling or circumstances present a weighty, difficult theme, can attest. As the thoughts pursue one another in the mind, attempts are made, and again abandoned; the state of the heart is somewhat like that of chaos before the creation. But when, finally, the right thought and the right utterance for it are found, that which is found appears to us, not as if self-discovered, but as a gift; we regard it with the feeling that a higher power has influenced our thoughts and imaginings; the confession by us, ἡ ἱκανότης ἡμῶν ἐκ τοῦ Θεοῦ (2-Corinthians 3:5), in so far as we believe in a living God, is inevitable.

From the Lord - Men can neither think nor speak wisely and well without Divine assistance.