Allah(swt), told us to make us realize

 وَقَالُواْ لَوْلا أُنزِلَ عَلَيْهِ مَلَكٌ وَلَوْ أَنزَلْنَا مَلَكًا لَّقُضِيَ الأمْرُ ثُمَّ لاَ يُنظَرُونَ 6:8

(Fathe Muhammad Jalandari)
اور کہتے ہيں کہ ان (پيغمبر) پر فرشتہ کيوں نازل نہ ہوا (جو ان کي تصديق کرتا) اگر ہم فرشتہ نازل کرتے تو کام ہي فيصل ہو جاتا پھر انھيں (مطلق) مہلت نہ دي جاتي 6:8

(Muhammad Assad)
 6:8 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.6:8

(Yousaf Ali)
 6:8 They say: "Why is not an angel sent down to him?" If we did send down an angel, the matter would be settled at once, and no respite would be granted them.6:8