The word(s) "fail" appears 37 time(s) in 37 verse(s) in Quran in Abdullah Yusuf Ali translation.

(21) Each of those gardens brought forth its produce, and failed not in the least therein: in the midst of them We caused a river to flow.

(22) "But we can surely produce magic to match thine! So make a tryst between us and thee, which we shall not fail to keep - neither we nor thou - in a place where both shall have even chances."

(23) (Moses) said: "Get thee gone! but thy (punishment) in this life will be that thou wilt say, 'touch me not'; and moreover (for a future penalty) thou hast a promise that will not fail: Now look at thy god, of whom thou hast become a devoted worshipper: We will certainly (melt) it in a blazing fire and scatter it broadcast in the sea!"

(24) Yet they ask thee to hasten on the Punishment! But Allah will not fail in His Promise. Verily a Day in the sight of thy Lord is like a thousand years of your reckoning.

(25) If anyone invokes, besides Allah, Any other god, he has no authority therefor; and his reckoning will be only with his Lord! and verily the Unbelievers will fail to win through!

(26) Those who rehearse the Book of Allah, establish regular Prayer, and spend (in Charity) out of what We have provided for them, secretly and openly, hope for a commerce that will never fail:

(27) It is Allah Who sustains the heavens and the earth, lest they cease (to function): and if they should fail, there is none - not one - can sustain them thereafter: Verily He is Most Forbearing, Oft-Forgiving.

(28) (This failing), they then sought a stratagem against him, but We made them the ones most humiliated!

(29) Truly such will be Our Bounty (to you); it will never fail;-

(30) "Did we treat them (as such) in ridicule, or have (our) eyes failed to perceive them?"