The word(s) "concern" appears 46 time(s) in 43 verse(s) in Quran in Mohsin Khan translation.

(1) And if you (Arab pagans, Jews, and Christians) are in doubt concerning that which We have sent down (i.e. the Qur'an) to Our slave (Muhammad صلى الله عليه وسلم), then produce a Surah (chapter) of the like thereof and call your witnesses (supporters and helpers) besides Allah, if you are truthful.

(2) But he who fears from a testator some unjust act or wrong-doing, and thereupon he makes peace between the parties concerned, there shall be no sin on him. Certainly, Allah is Oft-Forgiving, Most Merciful.

(3) And when My slaves ask you (O Muhammad صلى الله عليه وسلم) concerning Me, then (answer them), I am indeed near (to them by My Knowledge). I respond to the invocations of the supplicant when he calls on Me (without any mediator or intercessor). So let them obey Me and believe in Me, so that they may be led aright.

(4) Mankind were one community and Allah sent Prophets with glad tidings and warnings, and with them He sent down the Scripture in truth to judge between people in matters wherein they differed. And only those to whom (the Scripture) was given differed concerning it after clear proofs had come unto them through hatred, one to another. Then Allah by His Leave guided those who believed to the truth of that wherein they differed. And Allah guides whom He wills to the Straight Path.

(5) They ask you concerning fighting in the Sacred Months (i.e. 1st, 7th, 11th and 12th months of the Islamic calendar). Say "Fighting therein is a great (transgression) but a greater (transgression) with Allah is to prevent mankind from following the Way of Allah, to disbelieve in Him, to prevent access to Al-Masjid-Al-Haram (at Makkah), and to drive out its inhabitants, and Al-Fitnah is worse than killing. And they will never cease fighting you until they turn you back from your religion (Islamic Monotheism) if they can. And whosoever of you turns back from his religion and dies as a disbeliever, then his deeds will be lost in this life and in the Hereafter, and they will be the dwellers of the Fire. They will abide therein forever."

(6) They ask you (O Muhammad صلى الله عليه وسلم) concerning alcoholic drink and gambling. Say: "In them is a great sin, and (some) benefit for men, but the sin of them is greater than their benefit." And they ask you what they ought to spend. Say: "That which is beyond your needs." Thus Allah makes clear to you His Laws in order that you may give thought."

(7) In (to) this worldly life and in the Hereafter. And they ask you concerning orphans. Say: "The best thing is to work honestly in their property, and if you mix your affairs with theirs, then they are your brothers. And Allah knows him who means mischief (e.g. to swallow their property) from him who means good (e.g. to save their property). And if Allah had wished, He could have put you into difficulties. Truly, Allah is All-Mighty, All-Wise."

(8) They ask you concerning menstruation. Say: that is an Adha (a harmful thing for a husband to have a sexual intercourse with his wife while she is having her menses), therefore keep away from women during menses and go not unto them till they are purified (from menses and have taken a bath). And when they have purified themselves, then go in unto them as Allah has ordained for you (go in unto them in any manner as long as it is in their vagina). Truly, Allah loves those who turn unto Him in repentance and loves those who purify themselves (by taking a bath and cleaning and washing thoroughly their private parts, bodies, for their prayers).

(9) Then whoever disputes with you concerning him ['Îsa (Jesus)] after (all this) knowledge that has come to you [i.e. 'Îsa (Jesus) being a slave of Allah, and having no share in Divinity], say: (O Muhammad صلى الله عليه وسلم) "Come, let us call our sons and your sons, our women and your women, ourselves and yourselves - then we pray and invoke (sincerely) the Curse of Allah upon those who lie."

(10) Verily, you are those who have disputed about that of which you have knowledge. Why do you then dispute concerning that of which you have no knowledge? It is Allah Who knows, and you know not.