But I am poor and needy. In this concluding clause he mingles prayer with thanksgiving, although it may be that he records a request which he had made when he was placed in extreme danger. The first clause of the verse might be rendered thus: Although I was miserable and poor, God did think upon me. As according to the extent in which any one is afflicted, so is he despised by the world, we imagine that he is disregarded by God, we must, therefore, steadfastly maintain that our miseries in no respect produce on the part of God a feeling of weariness towards us, so that it should become troublesome to him to aid us. In this way, however, let us rather read the clause: When I was miserable and poor, the Lord looked upon my necessity: So that by this circumstance he enhances the grace of God. If God anticipate us with his goodness, and do not wait till adversity presses upon us, then his favor towards us is not so apparent. This comparison, therefore, illustrates very clearly the glory of God in the deliverance of David, inasmuch as he vouchsafed to stretch forth his hand to a man who was despised and rejected of all men, nay, who was destitute of all help and hope. Now, if it was necessary that David should have been reduced to this extremity, it is no wonder if persons in a more private station are often humbled after this manner, that they may feel and acknowledge in good earnest that they have been delivered out of despair by the hand of God. The simple and natural meaning of the prayer is this, Lord, thou art my help and my deliverer, therefore delay not to come to my aid. As it is a foolish thing to approach God with a doubtful and wavering mind, the Psalmist takes courage, as he was wont to do from his own experience, and persuades himself that the help of God, by which he had been hitherto preserved, would not fail him.

But I am poor and needy - More literally, "I am afflicted and poor." The language would describe the condition of one who was afflicted and was at the same time poor; of one who had no resource but in God, and who was passing through scenes of poverty and sorrow. There were undoubtedly times in the life of David to which this language would be applicable; but it would be far more applicable to the circumstances in which the Redeemer was placed; and, in accordance with the interpretation which has been given of the other parts of the psalm, I suppose that this is designed to represent his afflicted and humble condition as a man of poverty and sorrow.
Yet the Lord thinketh upon me - The Lord cares for me; he has not forgotten me. Man forsakes me, but he will not. Man leaves me to poverty and sorrow, but, he will not. How true this was of the Redeemer, that the Lord, the Father of mercies; thought on him, it is not needful now to say; nor can it be doubted that in the heavy sorrows of his life this was a source of habitual consolation. To others also - to all his friends - this is a source of unspeakable comfort. To be an object of the thoughts of God; to be had in his mind; to be constantly in his remembrance; to be certain that he will not forsake us in our trouble; to be assured in our own minds that one so great as God is - the infinite and eternal One - will never cease to think on us, may well sustain us in all the trials of life. It matters little who does forsake us, if he does not; it would be of little advantage to us who should think on us, if he did not.
Thou art my help and my deliverer - Implying the highest confidence. See the notes at Psalm 18:2.
Make no tarrying, O my God - Do not linger or delay in coining to my assistance. The psalm closes with this prayer. Applied to the Redeemer, it indicates strong confidence in God in the midst of his afflictions and sorrows, with earnest pleading, coming from the depth of those sorrows, that God would interpose for him. The vision of the psalmist extended here no farther. His eye rested on a suffering Messiah - afflicted, crushed, broken, forsaken - with all the woes connected with the work of human redemption, and all the sorrows expressive of the evil of sin clustering upon him, yet confident in God, and finding his last consolation in the feeling that God "thought" on him, and in the assurance that He would not ultimately forsake him. There is something delightful, though pensive, in the close of the psalm. The last prayer of the sufferer - the confident, earnest pleading - lingers on the ear, and we almost seem to behold the Sufferer in the depth of his sorrows, and in the earnestness of his supplication, calmly looking up to God as One that "thought" on him when all others had forgotten him; as a last, safe refuge when every other refuge had failed. So, in our sorrows, we may lie before the throne, calmly looking up to God with a feeling that we are not forgotten; that there is One who "thinks" on us; and that it is our privilege to pray to him that he would hasten to deliver us. All sorrow can be borne when we feel that God has not forgotten us; we may be calm when all the world forsakes us, if we can feel assured that the great and blessed God thinks on us, and will never cease to remember us.

But I am poor - עני ani, afflicted, greatly depressed.
And needy - אביון ebyon, a beggar. One utterly destitute, and seeking help.
The Lord thinketh upon me - The words are very emphatic; אדני Adonai, my prop, my support, thinketh, יחשב yachshab, meditateth, upon me. On which he concludes: "Thou art my help and deliverer." Seeing that my miserable state occupies thy heart, it will soon employ thy hand. Thou, who meditatest upon me, wilt deliver me.
Make no tarrying - Seeing thou art disposed to help, and I am in such great necessity, delay not, but come speedily to my assistance. The old Psalter speaks to this effect: "Let us not be so long under distress and misery that we lose our patience, or our love to thee."

But I am poor and needy,.... As Christ was literally, 2-Corinthians 8:9; and in a spiritual sense, when deserted by his Father, forsaken by his disciples, and surrounded by his enemies; and had the sins of his people, the curse of the law, and the wrath of God upon him;
yet the Lord thinketh upon me; thinketh good for me, as the Targum; or thinks highly of me; has me in great esteem though despised of men, and in such a suffering state;
thou art my help and my deliverer; he believed he should have what he prayed for, Psalm 40:13; see Isaiah 50:7;
make no tarrying, O my God; which is a repetition of the request in Psalm 40:13.

A summary of his condition and hopes.
thinketh upon--or provides for me. "He was heard," "when he had offered up prayers and supplications with strong crying and tears, unto Him that was able to save him from death" [Hebrews 5:7].

On Psalm 40:17 compare Psalm 35:27. David wishes, as he does in that passage, that the pious may most heartily rejoice in God, the goal of their longing; and that on account of the salvation that has become manifest, which they love (2-Timothy 4:8), they may continually say: Let Jahve become great, i.e., be magnified or celebrated with praises! In Psalm 40:17 with ואני he comes back to his own present helpless state, but only in order to contrast with it the confession of confident hope. True he is עני ואביון (as in Psalm 109:22; Psalm 136:1, cf. Psalm 25:16), but He who ruleth over all will care for him: Dominus solicitus erit pro me (Jerome). חשׁב in the same sense in which in Psalm 40:6 the מחשׁבות, i.e., God's thoughts of salvation, is conceived of (cf. the corresponding North-Palestinian expression in Jonah 1:6). A sigh for speedy help (אל־תּאחר, as in Daniel 9:19 with a transition of the merely tone-long Tsere into a pausal Pathach, and here in connection with a preceding closed syllable, Olshausen, 91, d, under the accompanying influence of two final letters which incline towards the a sound) closes this second part of the Psalm. The first part is nothing but thanksgiving, the second is exclusively prayer.