Mine eyes fail for thy salvation, and for the word of thy righteousness.
Mine eyes fall for thy salvation, and for the word of thy righteousness - i:e., for the fulfillment of 'thy Word,' which promises "salvation," a promise which "thy righteousness" ensures the fulfillment of. Compare also Psalms 119:121, which gives an additional reason why God's righteousness was engaged in his behalf-namely, the justice of his cause against his oppressors. Three things ought to be found in a promise, according to theologians:
(1) Truth, so as to promise sincerely;
(2) Faithfulness, to keep the promise;
(3) Justice, or righteousness, to give to him to whom you have promised his right or due, on the ground of the promise (Muis). "Fail for" -
i.e., faintingly long for.