And they say, "Why is a sign not sent down to him (10:20)

Almuntakhab Fi Tafsir Alquran Alkarim

They -the idolaters- insolently say: If only a sign other than the Quran be revealed to evince both his wisdom and the truth of his mission! Say to them O Muhammad: Divination of things to come rests in the hands of Allah Who knows the hidden, the unknown and all that is destined to come, therefore, you just wait O people, I will also await with you future events

Tafseer Tafheem-ul-Quran by Syed Abu-al-A'la Maududi

(10:20) They say: 'Why was a sign not sent down upon the prophet from His Lord? *27 Tell (such people): 'The realm of the Unseen belongs to Allah. Wait, then; I shall wait along with you. *28

And they say, "Why is a sign not sent down to him meaning

*27). The word 'sign' in the verse refers to the proof which supports a person's claim that he is a true Prophet and that his teaching is truly from God. In this connection it ought to be remembered that the demand of the unbelievers that the Prophet (peace be on him) should bring forth some sign to support his claim to be a Prophet was not made with sincerity, Their position was not that of a group of sincere people who were otherwise keen to accept the truth as soon as it became apparent to them, and who were ready to mould their own conduct, habits and social life according to its requirements, and all that they were waiting for was some sign, some proof, that would create in them a genuine conviction. The fact, on the contrary, was that the unbelievers' demand for miraculous signs was merely a pretext which they proffered in order to rationalize their disbelief. For they were sure to reject every sign, regardless of what that sign was, as unconvincing. Since they were hardened unbelievers, they were not prepared at all to accept such unseen truths as the unity of God and the Hereafter which would have led them to give up their
*28). The Prophet's statement conveys the idea that he had faithfully presented to them whatever God had revealed to him. As for the things which had not been revealed to the Prophet (peace be on him) they constitute ghayb (the realm of the unseen). Now, it is only God and none else who can decide whether to reveal any part of the ghayb ('the unseen') or not. Hence, if some people's believing was contingent upon their observing the signs which God had not revealed, then they might as well keep waiting indefinitely for those signs. The Prophet (peace be on him) would also wait and see whether God would yield to their adamant demands for miraculous signs or not.
 

And they say, "Why is a sign not sent down to him meaning in Urdu

اور یہ جو وہ کہتے ہیں کہ اِس نبیؐ پر اس کے رب کی طرف سے کوئی نشانی کیوں نہ اتاری گئی، تو ان سے کہو “غیب کا مالک و مختار تو اللہ ہی ہے، اچھا، انتظار کرو، میں بھی تمہارے ساتھ انتظار کرتا ہوں "