Al-A'raf 7:106

قَالَ إِن كُنتَ جِئْتَ بِـَٔايَةٍ فَأْتِ بِهَآ إِن كُنتَ مِنَ ٱلصَّـٰدِقِينَ

Qāla in kunta ji'ta biāyatin fati bihā in kunta mina l-ṣādiqīna

[Pharaoh] said, "If you have come with a sign, then bring it forth, if you should be of the truthful."