The word(s) "back" appears 262 time(s) in 241 verse(s) in Quran in Muhammad Habib Shakir translation.

(11) They ask you concerning the new moon. Say: They are times appointed for (the benefit of) men, and (for) the pilgrimage; and it is not righteousness that you should enter the houses at their backs, but righteousness is this that one should guard (against evil); and go into the houses by their doors and be careful (of your duty) to Allah, that you may be successful.

(12) And when he turns back, he runs along in the land that he may cause mischief in it and destroy the tilth and the stock, and Allah does not love mischief-making.

(13) They ask you concerning the sacred month about fighting in it. Say: Fighting in it is a grave matter, and hindering (men) from Allah's way and denying Him, and (hindering men from) the Sacred Mosque and turning its people out of it, are still graver with Allah, and persecution is graver than slaughter; and they will not cease fighting with you until they turn you back from your religion, if they can; and whoever of you turns back from his religion, then he dies while an unbeliever-- these it is whose works shall go for nothing in this world and the hereafter, and they are the inmates of the fire; therein they shall abide.

(14) Those who swear that they will not go in to their wives should wait four months; so if they go back, then Allah is surely Forgiving, Merciful.

(15) And the divorced women should keep themselves in waiting for three courses; and it is not lawful for them that they should conceal what Allah has created in their wombs, if they believe in Allah and the last day; and their husbands have a better right to take them back in the meanwhile if they wish for reconciliation; and they have rights similar to those against them in a just manner, and the men are a degree above them, and Allah is Mighty, Wise.

(16) But if you are in danger, then (say your prayers) on foot or on horseback; and when you are secure, then remember Allah, as He has taught you what you did not know.

(17) Have you not considered the chiefs of the children of Israel after Musa, when they said to a prophet of theirs: Raise up for us a king, (that) we may fight in the way of Allah. He said: May it not be that you would not fight if fighting is ordained for you? They said: And what reason have we that we should not fight in the way of Allah, and we have indeed been compelled to abandon our homes and our children. But when fighting was ordained for them, they turned back, except a few of them, and Allah knows the unjust.

(18) To make them walk in the right way is not incumbent on you, but Allah guides aright whom He pleases; and whatever good thing you spend, it is to your own good; and you do not spend but to seek Allah's pleasure; and whatever good things you spend shall be paid back to you in full, and you shall not be wronged.

(19) And guard yourselves against a day in which you shall be returned to Allah; then every soul shall be paid back in full what it has earned, and they shall not be dealt with unjustly.

(20) But if they dispute with you, say: I have submitted myself entirely to Allah and (so) every one who follows me; and say to those who have been given the Book and the unlearned people: Do you submit yourselves? So if they submit then indeed they follow the right way; and if they turn back, then upon you is only the delivery of the message and Allah sees the servants.