The word(s) "witness" appears 111 time(s) in 90 verse(s) in Quran in Muhammad Pickthal translation.

(31) I spake unto them only that which Thou commandedst me, (saying): Worship Allah, my Lord and your Lord. I was a witness of them while I dwelt among them, and when Thou tookest me Thou wast the Watcher over them. Thou art witness over all things.

(32) Say (O Muhammad): What thing is of most weight in testimony? Say: Allah is witness between me and you. And this Qur'an hath been inspired in me, that I may warn therewith you and whomsoever it may reach. Do ye in sooth bear witness that there are gods beside Allah? Say: I bear no such witness. Say: He is only One Allah. Lo! I am innocent of that which ye associate (with Him).

(33) And of the camels twain and of the oxen twain. Say: Hath He forbidden the two males or the two females, or that which the wombs of the two females contain; or were ye by to witness when Allah commanded you (all) this? Then who doth greater wrong than he who deviseth a lie concerning Allah, that he may lead mankind astray without knowledge. Lo! Allah guideth not wrongdoing folk.

(34) Say: Come, bring your witnesses who can bear witness that Allah forbade (all) this. And if they bear witness, do not thou bear witness with them. Follow thou not the whims of those who deny Our revelations, those who believe not in the Hereafter and deem (others) equal with their Lord.

(35) It is not for the idolaters to tend Allah's sanctuaries, bearing witness against themselves of disbelief. As for such, their works are vain and in the Fire they will abide.

(36) And as for those who chose a place of worship out of opposition and disbelief, and in order to cause dissent among the believers, and as an outpost for those who warred against Allah and His messenger aforetime, they will surely swear: We purposed naught save good. Allah beareth witness that they verily are liars.

(37) Allah sufficeth as a witness between us and you, that we were unaware of your worship.

(38) Whether We let thee (O Muhammad) behold something of that which We promise them or (whether We) cause thee to die, still unto Us is their return, and Allah, moreover, is witness over what they do.

(39) And thou (Muhammad) art not occupied with any business and thou recitest not a Lecture from this (Scripture), and ye (mankind) perform no act, but We are witness of you when ye are engaged therein. And not an atom's weight in the earth or in the sky escapeth your Lord, nor what is less than that or greater than that, but it is (written) in a clear Book.

(40) Is he (to be counted equal with them) who relieth on a clear proof from his Lord, and a witness from Him reciteth it, and before it was the Book of Moses, an example and a mercy? Such believe therein, and whoso disbelieveth therein of the clans, the Fire is his appointed place. So be not thou in doubt concerning it. Lo! it is the Truth from thy Lord; but most of mankind believe not.