Wa law nashaaa'u la-arainaakahum fala 'araftahum bi seemaahum; wa lata'rifan nahum fee lahnil qawl; wallaahu ya'lamu a'maalakum
Had We so wiled, We could have shown them up to thee, and thou shouldst have known them by their marks: but surely thou wilt know them by the tone of their speech! And Allah knows all that ye do.