The word(s) "once" appears 105 time(s) in 102 verse(s) in Quran in Mohsin Khan translation.

(91) Or say they: "He (Muhammad صلى الله عليه وسلم) has fabricated it." Say: "If I have fabricated it? still you have no power to support me against Allah. He knows best of what you say among yourselves concerning it (i.e. this Qur'an)! Sufficient is He as a witness between me and you! And He is the Oft-Forgiving, the Most Merciful."

(92) Then he conceived fear of them (when they ate not). They said: "Fear not." And they gave him glad tidings of a son having knowledge (about Allah and His religion of True Monotheism).

(93) Indeed Allah has heard the statement of her (Khaulah bint Tha'labah) that disputes with you (O Muhammad صلى الله عليه وسلم) concerning her husband (Aus bin As-Samit), and complains to Allah. And Allah hears the argument between you both. Verily, Allah is All-Hearer, All-Seer.

(94) O you who believe! Take not My enemies and your enemies (i.e. disbelievers and polytheists) as friends, showing affection towards them, while they have disbelieved in what has come to you of the truth (i.e. Islamic Monotheism, this Qur'an, and Muhammad صلى الله عليه وسلم), and have driven out the Messenger (Muhammad صلى الله عليه وسلم) and yourselves (from your homeland) because you believe in Allah your Lord! If you have come forth to strive in My Cause and to seek My Good Pleasure, (then take not these disbelievers and polytheists as your friends). You show friendship to them in secret, while I am All-Aware of what you conceal and what you reveal. And whosoever of you (Muslims) does that, then indeed he has gone (far) astray from the Straight Path .

(95) He knows what is in the heavens and on earth, and He knows what you conceal and what you reveal. And Allah is the All-Knower of what is in the breasts (of men).

(96) And if he (Muhammad صلى الله عليه وسلم) had forged a false saying concerning Us (Allah جل جلاله),

(97) A questioner asked concerning a torment about to befall

(98) Till, when they see that which they are promised, then they will know who it is that is weaker concerning helpers and less important concerning numbers.

(99) And once more let him be cursed: how he plotted!

(100) Move not your tongue concerning (the Qur'an, O Muhammad صلى الله عليه وسلم) to make haste therewith.