Complete Commentary on the Whole Bible, by Matthew Henry, at sacred-texts.com
(Psa 40:1-5) Confidence for deliverance.
(Psa 40:6-10) Christ's work of redemption.
(Psa 40:11-17) Prayer for mercy and grace.
Doubts and fears about the eternal state, are a horrible pit and miry clay, and have been so to many a dear child of God. There is power enough in God to help the weakest, and grace enough to help the unworthiest of all that trust in him. The psalmist waited patiently; he continued believing, hoping, and praying. This is applicable to Christ. His agony, in the garden and on the cross, was a horrible pit and miry clay. But those that wait patiently for God do not wait in vain. Those that have been under religious melancholy, and by the grace of God have been relieved, may apply Psa 40:2 very feelingly to themselves; they are brought up out of a horrible pit. Christ is the Rock on which a poor soul can alone stand fast. Where God has given stedfast hope, he expects there should be a steady, regular walk and conduct. God filled the psalmist with joy, as well as peace in believing. Multitudes, by faith beholding the sufferings and glory of Christ, have learned to fear the justice and trust in the mercy of God through Him. Many are the benefits with which we are daily loaded, both by the providence and by the grace of God.
The psalmist foretells that work of wonder, redemption by our Lord Jesus Christ. The Substance must come, which is Christ, who must bring that glory to God, and that grace to man, which it was impossible the sacrifices should ever do. Observe the setting apart of our Lord Jesus to the work and office of Mediator. In the volume, or roll, of the book it was written of him. In the close rolls of the Divine decrees and counsel, the covenant of redemption was recorded. Also, in all the volumes of the Old Testament something was written of him, Joh 19:28. Now the purchase of our salvation is made, the proclamation is sent forth, calling us to come and accept it. It was preached freely and openly. Whoever undertook to preach the gospel of Christ, would be under great temptation to conceal it; but Christ, and those he calls to that work, are carried on in it. May we believe his testimony, trust his promise, and submit to his authority.
The best saints see themselves undone, unless continually preserved by the grace of God. But see the frightful view the psalmist had of sin. This made the discovery of a Redeemer so welcome. In all his reflections upon each step of his life, he discovered something amiss. The sight and sense of our sins in their own colours, must distract us, if we have not at the same time some sight of a Saviour. If Christ has triumphed over our spiritual enemies, then we, through him, shall be more than conquerors. This may encourage all that seek God and love his salvation, to rejoice in him, and to praise him. No griefs nor poverty can render those miserable who fear the Lord. Their God, and all that he has or does, is the ground of their joy. The prayer of faith can unlock his fulness, which is adapted to all their wants. The promises are sure, the moment of fulfilment hastens forward. He who once came in great humility, shall come again in glorious majesty.