The word(s) "concern" appears 52 time(s) in 50 verse(s) in Quran in Abdullah Yusuf Ali translation.

(41) Only those wish to hasten it who believe not in it: those who believe hold it in awe, and know that it is the Truth. Behold, verily those that dispute concerning the Hour are far astray.

(42) Will ye then dispute with him concerning what he saw?

(43) Then will no (soul) entertain falsehood concerning its coming.

(44) Allah has indeed heard (and accepted) the statement of the woman who pleads with thee concerning her husband and carries her complaint (in prayer) to Allah: and Allah (always) hears the arguments between both sides among you: for Allah hears and sees (all things).

(45) We have sent to you, (O men!) a messenger, to be a witness concerning you, even as We sent a messenger to Pharaoh.

(46) Move not thy tongue concerning the (Qur'an) to make haste therewith.

(47) concerning what are they disputing?

(48) concerning the Great News,

(49) Wherein art thou (concerned) with the declaration thereof?

(50) Each one of them, that Day, will have enough concern (of his own) to make him indifferent to the others.