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

(41) The holders back from among the believers, not having any injury, and those who strive hard in Allah's way with their property and their persons are not equal; Allah has made the strivers with their property and their persons to excel the holders back a (high) degree, and to each (class) Allah has promised good; and Allah shall grant to the strivers above the holders back a mighty reward:

(42) O my people! enter the holy land which Allah has prescribed for you and turn not on your backs for then you will turn back losers.

(43) And how do they make you a judge and they have the Taurat wherein is Allah's judgment? Yet they turn back after that, and these are not the believers.

(44) And that you should judge between them by what Allah has revealed, and do not follow their low desires, and be cautious of them, lest they seduce you from part of what Allah has revealed to you; but if they turn back, then know that Allah desires to afflict them on account of some of their faults; and most surely many of the people are transgressors.

(45) O you who believe! whoever from among you turns back from his religion, then Allah will bring a people, He shall love them and they shall love Him, lowly before the believers, mighty against the unbelievers, they shall strive hard in Allah's way and shall not fear the censure of any censurer; this is Allah's Face, He gives it to whom He pleases, and Allah is Ample-giving, Knowing.

(46) And obey Allah and obey the apostle and be cautious; but if you turn back, then know that only a clear deliverance of the message is (incumbent) on Our apostle.

(47) And could you see when they are made to stand before the fire, then they shall say: Would that we were sent back, and we would not reject the communications of our Lord and we would be of the believers.

(48) Nay, what they concealed before shall become manifest to them; and if they were sent back, they would certainly go back to that which they are forbidden, and most surely they are liars.

(49) They are losers indeed who reject the meeting of Allah; until when the hour comes upon them all of a sudden they shall say: O our grief for our neglecting it! and they shall bear their burdens on their backs; now surely evil is that which they bear.

(50) Then are they sent back to Allah, their Master, the True one; now surely His is the judgment and He is swiftest in taking account.