Surah Yunus — Ayah 20 (10:20)
وَيَقُولُونَ لَوۡلَآ أُنزِلَ عَلَيۡهِ ءَايَةٞ مِّن رَّبِّهِۦۖ فَقُلۡ إِنَّمَا ٱلۡغَيۡبُ لِلَّهِ فَٱنتَظِرُوٓاْ إِنِّي مَعَكُم مِّنَ ٱلۡمُنتَظِرِينَ ٢٠
English translation (Saheeh International)
And they say, "Why is a sign not sent down to him from his Lord?" So say, "The unseen is only for Allāh [to administer], so wait; indeed, I am with you among those who wait."
Brief commentary
The idolaters ask why a sign is not sent to Muhammad from his Lord to prove the truth of what he says. Say to them O Messenger, 'The sending down of signs is Allah’s knowledge alone, so wait for the sign you ask for, as I am also waiting along with you for it.'