Psalms 39:7

The psalmist, having meditated on the shortness and uncertainty of life, and the vanity and vexation of spirit that attend all the comforts of life, here, in these verses, turns his eyes and heart heaven-ward. When there is no solid satisfaction to be had in the creature it is to be found in God, and in communion with him; and to him we should be driven by our disappointments in the world. David here expresses, I. His dependence on God, Psa 39:7. Seeing all is vanity, and man himself is so, 1. He despairs of a happiness in the things of the world, and disclaims all expectations from it: "Now, Lord, what wait I for? Even nothing from the things of sense and time; I have nothing to wish for, nothing to hope for, from this earth." Note, The consideration of the vanity and frailty of human life should deaden our desires to the things of this world and lower our expectations from it. "If the world be such a thing as this, God deliver me from having, or seeking, my portion in it." We cannot reckon upon constant health and prosperity, nor upon comfort in any relation; for it is all as uncertain as our continuance here. "Though I have sometimes foolishly promised myself this and the other from the world, I am now of another mind." 2. He takes hold of happiness and satisfaction in God: My hope is in thee.

— Matthew Henry's Concise Commentary (public domain)

The interrogation makes the implied negative stronger. Though this world offers nothing to our expectation, God is worthy of all confidence.

— Jamieson-Fausset-Brown Commentary (public domain)