My soul fainteth for thy salvation - The new division of the psalm, which begins here, is indicated by the Hebrew letter Kaph (כ k), equivalent to “k” or “c” (hard). The word here rendered “fainteth” is the same that in Psalms 73:26 is translated “faileth”: “My flesh and my heart faileth.” The idea is, that his strength gave way; he had such an intense desire for salvation that he became weak and powerless. Any strong emotion may thus prostrate us; and the love of God - the desire of his favor - the longing for heaven - may be so intense as to produce this result.
I hope in thy word - I trust in thy promises, and am sustained. My powers, which would otherwise wholly fail, are upheld by thy word, and on that I rely. See Psalms 119:74.