Charles H. Spurgeon on Psalms 119:81

The whole eight verses, 81-89. The eleventh letter, Caph, signifies the hollowed hand. The expositors, however, looking only to the meaning curved, which is but half of its import, explain the section as signifying the act of bowing down in penitence, or as noting that the fathers of the Old Testament were like veteran soldiers, stooping with years and toil, and bowed down yet further by the heavy weight of the law, only removable by that coming of Christ for which they prayed. Others extend the notion to the saints of the church, weighed down by the sorrows and cares of this life, and therefore desiring to be dissolved and to be with Christ. The true meaning is to be sought in the full interpretation of the word; for the hand is hollowed either in order to retain something which actually lies in it, or to receive something about to be placed in it by another. Thus the hand may be God's, as the giver of bounty, or man's, as the receiver of it; and the whole scope of the section, as a prayer for speedy help, is that man holds out his hand as a beggar, supplicating the mercy of God. Jerome, Ambrose, and others, in Neale and Littledale.

My soul fainteth for thy salvation. 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 favour, the longing for heaven, may be so intense as to produce this result. Albert Barnes.