The word(s) "why" appears 71 time(s) in 69 verse(s) in Quran in Saheeh International translation.

(1) And when it is said to them, "Believe in what Allah has revealed," they say, "We believe [only] in what was revealed to us." And they disbelieve in what came after it, while it is the truth confirming that which is with them. Say, "Then why did you kill the prophets of Allah before, if you are [indeed] believers?"

(2) Those who do not know say, "why does Allah not speak to us or there come to us a sign?" Thus spoke those before them like their words. Their hearts resemble each other. We have shown clearly the signs to a people who are certain [in faith].

(3) Have you not considered the assembly of the Children of Israel after [the time of] Moses when they said to a prophet of theirs, "Send to us a king, and we will fight in the way of Allah "? He said, "Would you perhaps refrain from fighting if fighting was prescribed for you?" They said, "And why should we not fight in the cause of Allah when we have been driven out from our homes and from our children?" But when fighting was prescribed for them, they turned away, except for a few of them. And Allah is Knowing of the wrongdoers.

(4) O People of the Scripture, why do you argue about Abraham while the Torah and the Gospel were not revealed until after him? Then will you not reason?

(5) Here you are - those who have argued about that of which you have [some] knowledge, but why do you argue about that of which you have no knowledge? And Allah knows, while you know not.

(6) O People of the Scripture, why do you disbelieve in the verses of Allah while you witness [to their truth]?

(7) O People of the Scripture, why do you confuse the truth with falsehood and conceal the truth while you know [it]?

(8) Say, "O People of the Scripture, why do you disbelieve in the verses of Allah while Allah is Witness over what you do?"

(9) Say, "O People of the Scripture, why do you avert from the way of Allah those who believe, seeking to make it [seem] deviant, while you are witnesses [to the truth]? And Allah is not unaware of what you do."

(10) why [is it that] when a [single] disaster struck you [on the day of Uhud], although you had struck [the enemy in the battle of Badr] with one twice as great, you said, "From where is this?" Say, "It is from yourselves." Indeed, Allah is over all things competent.