The word(s) "witnesses" appears 27 time(s) in 23 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) Or were you witnesses when death approached Ya'qub (Jacob)? When he said unto his sons, "What will you worship after me?" They said, "We shall worship your Ilah (God - Allah), the Ilah (God) of your fathers, Ibrahim (Abraham), Isma'il (Ishmael), Ishaq (Isaac), One Ilah (God), and to Him we submit (in Islam)."

(3) Thus We have made you [true Muslims - real believers of Islamic Monotheism, true followers of Prophet Muhammad صلى الله عليه وسلم and his Sunnah (legal ways)], a just (and the best) nation, that you be witnesses over mankind and the Messenger (Muhammad صلى الله عليه وسلم) be a witness over you. And We made the Qiblah (prayer direction towards Jerusalem) which you used to face, only to test those who followed the Messenger (Muhammad صلى الله عليه وسلم) from those who would turn on their heels (i.e. disobey the Messenger). Indeed it was great (heavy) except for those whom Allah guided. And Allah would never make your faith (prayers) to be lost (i.e. your prayers offered towards Jerusalem). Truly, Allah is full of Kindness, the Most Merciful towards mankind.

(4) O you who believe! When you contract a debt for a fixed period, write it down. Let a scribe write it down in justice between you. Let not the scribe refuse to write as Allah has taught him, so let him write. Let him (the debtor) who incurs the liability dictate, and he must fear Allah, his Lord, and diminish not anything of what he owes. But if the debtor is of poor understanding, or weak, or is unable to dictate for himself, then let his guardian dictate in justice. And get two witnesses out of your own men. And if there are not two men (available), then a man and two women, such as you agree for witnesses, so that if one of them (two women) errs, the other can remind her. And the witnesses should not refuse when they are called (for evidence). You should not become weary to write it (your contract), whether it be small or big, for its fixed term, that is more just with Allah; more solid as evidence, and more convenient to prevent doubts among yourselves, save when it is a present trade which you carry out on the spot among yourselves, then there is no sin on you if you do not write it down. But take witnesses whenever you make a commercial contract. Let neither scribe nor witness suffer any harm, but if you do (such harm), it would be wickedness in you. So be afraid of Allah; and Allah teaches you. And Allah is the All-Knower of each and everything.

(5) And (remember) when Allah took the Covenant of the Prophets, saying: "Take whatever I gave you from the Book and Hikmah (understanding of the Laws of Allah), and afterwards there will come to you a Messenger (Muhammad صلى الله عليه وسلم) confirming what is with you; you must, then, believe in him and help him." Allah said: "Do you agree (to it) and will you take up My Covenant (which I conclude with you)?" They said: "We agree." He said: "Then bear witness; and I am with you among the witnesses (for this)."

(6) Say: "O people of the Scripture (Jews and Christians)! Why do you stop those who have believed, from the Path of Allah, seeking to make it seem crooked, while you (yourselves) are witnesses [to Muhammad صلى الله عليه وسلم as a Messenger of Allah and Islam (Allah's religion, i.e. to worship none but Him Alone)]? And Allah is not unaware of what you do."

(7) And those of your women who commit illegal sexual intercourse, take the evidence of four witnesses from amongst you against them; and if they testify, confine them (i.e. women) to houses until death comes to them or Allah ordains for them some (other) way.

(8) O you who believe! Stand out firmly for justice, as witnesses to Allah, even though it be against yourselves, or your parents, or your kin, be he rich or poor, Allah is a Better Protector to both (than you). So follow not the lusts (of your hearts), lest you avoid justice; and if you distort your witness or refuse to give it, verily, Allah is Ever Well-Acquainted with what you do.

(9) O you who believe! Stand out firmly for Allah as just witnesses; and let not the enmity and hatred of others make you avoid justice. Be just: that is nearer to piety; and fear Allah. Verily, Allah is Well-Acquainted with what you do.

(10) Verily, We did send down the Taurat (Torah) [to Musa (Moses)], therein was guidance and light, by which the Prophets, who submitted themselves to Allah's Will, judged for the Jews. And the rabbis and the priests [too judged for the Jews by the Taurat (Torah) after those Prophets], for to them was entrusted the protection of Allah's Book, and they were witnesses thereto. Therefore fear not men but fear Me (O Jews) and sell not My Verses for a miserable price. And whosoever does not judge by what Allah has revealed, such are the Kafirun (i.e. disbelievers - of a lesser degree as they do not act on Allah's Laws).