David here comforts himself with three things:—
I. The favour God bears to his humble people (Ps. 138:6): Though the Lord be high, and neither needs any of his creatures nor can be benefited by them, yet has he respect unto the lowly, smiles upon them as well pleased with them, overlooks heaven and earth to cast a gracious look upon them (Isa. 57:15; 66:1), and, sooner or later, he will put honour upon them, while he knows the proud afar off, knows them, but disowns them and rejects them, how proudly soever they pretend to his favour. Dr. Hammond makes this to be the sum of that gospel which the kings of the earth shall hear and welcome—that penitent sinners shall be accepted of God, but the impenitent cast out; witness the instance of the Pharisee and the publican, Luke 18:9-14
II. The care God takes of his afflicted oppressed people, Ps. 138:7. David, though a great and good man, expects to walk in the midst of trouble, but encourages himself with hope, 1. That God would comfort him: “When my spirit is ready to sink and fail, thou shalt revive me, and make me easy and cheerful under my troubles.” Divine consolations have enough in them to revive us even when we walk in the midst of troubles and are ready to die away for fear. 2. That he would protect him, and plead his cause: “Thou shalt stretch forth thy hand, though not against my enemies to destroy them, yet against the wrath of my enemies, to restrain that and set bounds to it.” 3. That he would in due time work deliverance for him: Thy right hand shall save me. As he has one hand to stretch out against his enemies, so he has another to save his own people. Christ is the right hand of the Lord, that shall save all those who serve him.
III. The assurance we have that whatever good work God has begun in and for his people he will perform it (Ps. 138:8): The Lord will perfect that which concerns me, 1. That which is most needful for me; and he knows best what is so. We are careful and cumbered about many things that do not concern us, but he knows what are the things that really are of consequence to us (Matt. 6:32) and he will order them for the best. 2. That which we are most concerned about. Every good man is most concerned about his duty to God and his happiness in God, that the former may be faithfully done and the latter effectually secured; and if indeed these are the things that our hearts are most upon, and concerning which we are most solicitous, there is a good work begun in us, and he that has begun it will perfect it, we may be confident he will, Phil. 1:6. Observe, (1.) What ground the psalmist builds this confidence upon: Thy mercy, O Lord! endures for ever. This he had made very much the matter of his praise (Ps. 13:6), and therefore he could here with the more assurance make it the matter of his hope. For, if we give God the glory of his mercy, we may take to ourselves the comfort of it. Our hopes that we shall persevere must be founded, not upon our own strength, for that will fail us, but upon the mercy of God, for that will not fail. It is well pleaded, “Lord, thy mercy endures for ever; let me be for ever a monument of it.” (2.) What use he makes of this confidence; it does not supersede, but quicken prayer; he turns his expectation into a petition: “Forsake not, do not let go, the work of thy own hands. Lord, I am the work of thy own hands, my soul is so, do not forsake me; my concerns are so, do not lay by thy care of them.” Whatever good there is in us it is the work of God’s own hands; he works in us both to will and to do; it will fail if he forsake it; but his glory, as Jehovah, a perfecting God, is so much concerned in the progress of it to the end that we may in faith pray, “Lord, do not forsake it.” Whom he loves he loves to the end; and, as for God, his work is perfect.