| Barnes' Notes on the Bible Behold, I have longed after thy precepts - I have earnestly desired them. See the notes at Psalm 119:20. Quicken me in thy righteousness - Make me to live; to live in obedience to thy righteous laws. See Psalm 119:25, note; Psalm 119:37, note.
Clarke's Commentary on the BibleBehold, I have longed - Thou searchest the heart; thou knowest that I have long desired thy salvation; thou seest that this desire still remains. Behold it! it is thy work; and through thy mercy I breathe after thy mercy. Quicken me - I am dying; O give me the spirit of life in Christ Jesus!
Gill's Exposition of the Entire BibleBehold, I have longed after thy precepts,.... After a greater degree of knowledge of them, and an opportunity of hearing them explained and enforced, and of yielding obedience to them; see Psalm 119:7; quicken me in thy righteousness: in the way of righteousness, according to the word of righteousness, the Gospel, and with the righteousness of Christ revealed in it; and which is unto life, and quickens and comforts the heart, and from whence abundance of peace and joy flows.
Geneva Study BibleBehold, I have longed after thy precepts: {f} quicken me in thy righteousness. (f) Give me strength to continue in your word even to the end.
Wesley's Notes 119:40 Longed - After a more solid knowledge and constant performance of them. In - According to thy faithfulness.
Matthew Henry's Concise Commentary119:33-40 Teach me thy statutes, not the mere words, but the way of applying them to myself. God, by his Spirit, gives a right understanding. But the Spirit of revelation in the word will not suffice, unless we have the Spirit of wisdom in the heart. God puts his Spirit within us, causing us to walk in his statutes. The sin here prayed against is covetousness. Those that would have the love of God rooted in them, must get the love of the world rooted out; for the friendship of the world is enmity with God. Quicken me in thy way; to redeem time, and to do every duty with liveliness of spirit. Beholding vanity deadens us, and slackens our pace; a traveller must not stand gazing upon every object that presents itself to his view. The promises of God's word greatly relate to the preservation of the true believer. When Satan has drawn a child of God into worldly compliances, he will reproach him with the falls into which he led him. Victory must come from the cross of Christ. When we enjoy the sweetness of God's precepts, it will make us long for more acquaintance with them. And where God has wrought to will, he will work to do. | 
