Verse 30

وَلَوْ نَشَآءُ لَأَرَيْنَـٰكَهُمْ فَلَعَرَفْتَهُم بِسِيمَـٰهُمْ وَلَتَعْرِفَنَّهُمْ فِى لَحْنِ ٱلْقَوْلِ وَٱللَّهُ يَعْلَمُ أَعْمَـٰلَكُمْ

Had We willed, We could have exposed them for you, then, you would have recognized them by their looks and by the way they talk. And God knows all your work.