The word(s) "convincing" appears 4 time(s) in 4 verse(s) in Quran in Abdullah Yusuf Ali translation.

(1) O mankind! verily there hath come to you a convincing proof from your Lord: For We have sent unto you a light (that is) manifest.

(سورة النساء, An-Nisaa, Chapter #4, Verse #174)
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(2) "These our people have taken for worship gods other than Him: why do they not bring forward an authority clear (and convincing) for what they do? Who doth more wrong than such as invent a falsehood against Allah?

(سورة الكهف, Al-Kahf, Chapter #18, Verse #15)
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(3) Or have they taken for worship (other) gods besides him? Say, "Bring your convincing proof: this is the Message of those with me and the Message of those before me." But most of them know not the Truth, and so turn away.

(سورة الأنبياء, Al-Anbiyaa, Chapter #21, Verse #24)
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(4) (Moses) said: "Even if I showed you something clear (and) convincing?"

(سورة الشعراء, Ash-Shu'araa, Chapter #26, Verse #30)
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