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

(41) It is not fitting for a man that Allah should speak to him except by inspiration, or from behind a veil, or by the sending of a messenger to reveal, with Allah's permission, what Allah wills: for He is Most High, Most Wise.

(42) How many were the gardens and springs they left behind,

(43) The desert Arabs who lagged behind will say to thee: "We were engaged in (looking after) our flocks and herds, and our families: do thou then ask forgiveness for us." They say with their tongues what is not in their hearts. Say: "Who then has any power at all (to intervene) on your behalf with Allah, if His Will is to give you some loss or to give you some profit? But Allah is well acquainted with all that ye do.

(44) Those who lagged behind (will say), when ye (are free to) march and take booty (in war): "Permit us to follow you." They wish to change Allah's decree: Say: "Not thus will ye follow us: Allah has already declared (this) beforehand": then they will say, "But ye are jealous of us." Nay, but little do they understand (such things).

(45) Say to the desert Arabs who lagged behind: "Ye shall be summoned (to fight) against a people given to vehement war: then shall ye fight, or they shall submit. Then if ye show obedience, Allah will grant you a goodly reward, but if ye turn back as ye did before, He will punish you with a grievous Penalty."

(46) O ye who believe! Avoid suspicion as much (as possible): for suspicion in some cases is a sin: And spy not on each other behind their backs. Would any of you like to eat the flesh of his dead brother? Nay, ye would abhor it... But fear Allah: For Allah is Oft-Returning, Most Merciful.

(47) They will not fight you (even) together, except in fortified townships, or from behind walls. Strong is their fighting (spirit) amongst themselves: thou wouldst think they were united, but their hearts are divided: that is because they are a people devoid of wisdom.

(48) "Except a messenger whom He has chosen: and then He makes a band of watchers march before him and behind him,

(49) To any of you that chooses to press forward, or to follow behind;-

(50) As to these, they love the fleeting life, and put away behind them a Day (that will be) hard.