A Commentary, Critical, Practical, and Explanatory on the Old and New Testaments, by Robert Jamieson, A.R. Fausset and David Brown  at sacred-texts.com
pro 3:1The study of truth commended. God must be feared, honored, and trusted, and filial submission, under chastisement, exhibited. The excellence of wisdom urged and illustrated by its place in the divine counsels. Piety enforced by a contrast of the destiny of the righteous and the wicked. (Pro. 3:1-35)
law [and] commandments--all divine instructions (see on Psa 119:1 and Psa 119:4).
let thine heart keep--or sincerely observe (Pro 4:13; Pro 5:2).
pro 3:2length . . . life--often promised as blessings (Psa 21:4; Psa 91:16).
peace--includes prosperity (Psa 125:5).
add--abound to thee.
pro 3:3mercy and truth--God's faithfulness to His promises is often expressed by these terms (Psa 25:10; Psa 57:3). As attributes of men, they express integrity in a wide sense (Pro 16:6; Pro 20:28).
bind . . . write . . . heart--outwardly adorn and inwardly govern motives.
pro 3:4favour--grace, amiability (Pro 22:11; Psa 45:2); united with this,
a good understanding--(Compare Margin), a discrimination, which secures success.
in the sight . . . man--such as God and man approve.
pro 3:5Trust . . . heart--This is the center and marrow of true wisdom (Pro 22:19; Pro 28:25). The positive duty has its corresponding negation in the admonition against self-confidence.
pro 3:6ways-- (Psa 1:1).
acknowledge--by seeking His wise aid (Pro 16:3; Psa 37:5; Jer 9:23-24).
direct--literally, "make plain" (compare Heb 12:13).
pro 3:7(Compare Pro 27:2; Rom 12:16).
fear . . . evil--reverentially regarding His law.
pro 3:8It--This conduct.
to thy navel--for all the organs of nourishment.
bones--frame of body. True piety promotes bodily health.
pro 3:9(Compare Pro 11:25; Exo 23:19; Deu 18:4; Isa 32:8; Co2 9:13).
pro 3:10presses--or wine fats (Joe 2:24; Joe 3:13).
pro 3:11The true intent of afflictions considered; they do not contradict the assertion of the blessed state of the pious (Job 5:17; Heb 12:5-6).
pro 3:12he delighteth--or receiveth as denoting reconciliation regarding the offense which produced chastisement.
pro 3:13findeth--literally, "reaches," or "obtains by seeking."
getteth--literally, "draws out," as metals by digging.
pro 3:14The figure of Pro 3:13 carried out.
it--that is, wisdom.
merchandise of silver--acquisition by trading.
fine gold--dug gold, solid as a nugget.
pro 3:15rubies--gems, or pearls.
pro 3:16Wisdom personified as bringing the best blessings (compare Mat 6:33; Ti1 4:8).
pro 3:17Her ways--such as she directs us to take.
pro 3:18Wisdom allegorized as
a tree of life-- (Gen 2:9; Gen 3:22) whose fruit preserves life, gives all that makes living a blessing.
pro 3:19The place of wisdom in the economy of creation and providence commends it to men, who, in proportion to their finite powers, may possess this invaluable attribute, and are thus encouraged by the divine example of its use to seek its possession.
pro 3:21sound wisdom--(compare Pro 2:7).
let . . . eyes--that is, these words of instruction.
pro 3:22assign reasons in their value for happiness and ornament, guidance and support in dangers, both when waking and sleeping.
pro 3:25Be not--or, "You shall not be."
sudden fear--what causes it (Pro 1:27), any unlooked-for evil (Psa 46:3; Psa 91:12; Pe1 3:14).
desolation-- (Pro 1:27).
pro 3:26The reason; such as are objects of God's favor.
be thy confidence--literally, "in thy confidence," in the source of thy strength (compare Nah 3:9, for the same construction, Hebrew).
pro 3:27Promptly fulfil all obligations both of justice and charity (compare Jam 2:15-16).
pro 3:29Do not abuse confidence and avoid litigation.
pro 3:31oppressor--or man of mischief. The destiny of successful evildoers warns against desiring their lot (Psa 37:1-2, Psa 37:35-36).
pro 3:32Reasons for the warning.
froward-- (Pro 2:15).
secret . . . righteous--in their communion (Amo 3:7).
pro 3:33curse . . . wicked--It abides with them, and will be manifested.
pro 3:34The retribution of sinners, as in Psa 18:26.
pro 3:35inherit--as a portion.
shame--or disgrace, as opposed to honor.
promotion--(Compare Margin); as honor for well-doing makes men conspicuous, so fools are signalized by disgrace.