The word(s) "back" appears 225 time(s) in 216 verse(s) in Quran in Abdullah Yusuf Ali translation.

(41) O ye who believe! Call in remembrance the favour of Allah unto you when certain men formed the design to stretch out their hands against you, but (Allah) held back their hands from you: so fear Allah. And on Allah let believers put (all) their trust.

(42) "O my people! Enter the holy land which Allah hath assigned unto you, and turn not back ignominiously, for then will ye be overthrown, to your own ruin."

(43) O ye who believe! if any from among you turn back from his Faith, soon will Allah produce a people whom He will love as they will love Him,- lowly with the believers, mighty against the rejecters, fighting in the way of Allah, and never afraid of the reproaches of such as find fault. That is the grace of Allah, which He will bestow on whom He pleaseth. And Allah encompasseth all, and He knoweth all things.

(44) Obey Allah, and obey the Messenger, and beware (of evil): if ye do turn back, know ye that it is Our Messenger's duty to proclaim (the message) in the clearest manner.

(45) Lawful to you is the pursuit of water-game and its use for food,- for the benefit of yourselves and those who travel; but forbidden is the pursuit of land-game;- as long as ye are in the sacred precincts or in pilgrim garb. And fear Allah, to Whom ye shall be gathered back.

(46) If thou couldst but see when they are confronted with the Fire! They will say: "Would that we were but sent back! Then would we not reject the signs of our Lord, but would be amongst those who believe!"

(47) Lost indeed are they who treat it as a falsehood that they must meet Allah,- until on a sudden the hour is on them, and they say: "Ah! woe unto us that we took no thought of it"; for they bear their burdens on their backs, and evil indeed are the burdens that they bear?

(48) For those who followed the Jewish Law, We forbade every (animal) with undivided hoof, and We forbade them that fat of the ox and the sheep, except what adheres to their backs or their entrails, or is mixed up with a bone: this in recompense for their wilful disobedience: for We are true (in Our ordinances).

(49) If they accuse thee of falsehood, say: "Your Lord is full of mercy all-embracing; but from people in guilt never will His wrath be turned back.

(50) Do they just wait for the final fulfilment of the event? On the day the event is finally fulfilled, those who disregarded it before will say: "The messengers of our Lord did indeed bring true (tidings). Have we no intercessors now to intercede on our behalf? Or could we be sent back? then should we behave differently from our behaviour in the past." In fact they will have lost their souls, and the things they invented will leave them in the lurch.