The word(s) "behind" appears 53 time(s) in 52 verse(s) in Quran in Abdullah Yusuf Ali translation.

(11) If they had intended to come out, they would certainly have made some preparation therefor; but Allah was averse to their being sent forth; so He made them lag behind, and they were told, "Sit ye among those who sit (inactive)."

(12) Those who were left behind (in the Tabuk expedition) rejoiced in their inaction behind the back of the Messenger of Allah: they hated to strive and fight, with their goods and their persons, in the cause of Allah: they said, "Go not forth in the heat." Say, "The fire of Hell is fiercer in heat." If only they could understand!

(13) If, then, Allah bring thee back to any of them, and they ask thy permission to come out (with thee), say: "Never shall ye come out with me, nor fight an enemy with me: for ye preferred to sit inactive on the first occasion: Then sit ye (now) with those who lag behind."

(14) When a Sura comes down, enjoining them to believe in Allah and to strive and fight along with His Messenger, those with wealth and influence among them ask thee for exemption, and say: "Leave us (behind): we would be with those who sit (at home)."

(15) They prefer to be with (the women), who remain behind (at home): their hearts are sealed and so they understand not.

(16) The ground (of complaint) is against such as claim exemption while they are rich. They prefer to stay with the (women) who remain behind: Allah hath sealed their hearts; so they know not (What they miss).

(17) (He turned in mercy also) to the three who were left behind; (they felt guilty) to such a degree that the earth seemed constrained to them, for all its spaciousness, and their (very) souls seemed straitened to them,- and they perceived that there is no fleeing from Allah (and no refuge) but to Himself. Then He turned to them, that they might repent: for Allah is Oft-Returning, Most Merciful.

(18) Nor should the Believers all go forth together: if a contingent from every expedition remained behind, they could devote themselves to studies in religion, and admonish the people when they return to them,- that thus they (may learn) to guard themselves (against evil).

(19) (The Messengers) said: "O Lut! We are Messengers from thy Lord! By no means shall they reach thee! now travel with thy family while yet a part of the night remains, and let not any of you look back: but thy wife (will remain behind): To her will happen what happens to the people. Morning is their time appointed: Is not the morning nigh?"

(20) He said: "O my people! is then my family of more consideration with you than Allah? For ye cast Him away behind your backs (with contempt). But verily my Lord encompasseth on all sides all that ye do!