سُورَةُ الأَنۡعَامِ
Al-An'aam·6:8
وَقَالُوا لَوْلَا أُنْزِلَ عَلَيْهِ مَلَكٌ ۖ وَلَوْ أَنْزَلْنَا مَلَكًا لَقُضِيَ الْأَمْرُ ثُمَّ لَا يُنْظَرُونَ٨
They are saying, too, "Why has not an angel (visibly] been sent down unto him?" But had we sent down an angel, all would indeed have been decided, and they would have been allowed no further respite [for repentance.