Surat Yunus (19-20)

{وَمَا كَانَ النَّاسُ إِلاَّ أُمَّةً وَاحِدَةً فَاخْتَلَفُواْ وَلَوْلاَ كَلِمَةٌ سَبَقَتْ مِن رَّبِّكَ لَقُضِيَ بَيْنَهُمْ فِيمَا فِيهِ يَخْتَلِفُونَ} (يونس : 19)

19- People had one creed which was the creed of Islam then some of them associated partners with Allah in worship. From that point on, there were Muslims and non-Muslims who differed. Had it been for the decree of Allah that judging between them shall be on the Day of Recompense, difference would have ended in the world by sending down Ayahs to indicate the truth of every issue or by destroying the falsehood and keeping the truth.

{وَيَقُولُونَ لَوْلاَ أُنزِلَ عَلَيْهِ آيَةٌ مِّن رَّبِّهِ فَقُلْ إِنَّمَا الْغَيْبُ لِلّهِ فَانْتَظِرُواْ إِنِّي مَعَكُم مِّنَ الْمُنتَظِرِينَ} (يونس : 20)

20- Those stubborn disbelievers say: If Muhammad is a true Prophet, he should bring a miracle along with his prophethood such as the stick of Moses or turn the mountain of Safa into gold or turn the mountains of Makkah into gardens and rivers. They said so out of stubbornness not to embrace Islam because the Prophet had numerous miracles.

O Prophet, tell them: The whole matter is in the hands of Allah who knows the consequences of all matters, so wait for the judgment of Allah about you.

They would not have believed even if their request was responded, and if they had not believed, Allah would have destroyed them, but He was kind to them and delayed them until they embraced Islam.