
From the life of Hazrat Umar (ra) bin Khattab
The commanders of the Muslim army were informed that they should come and meet in Jabiya. In accordance with this announcement, Yazid bin Abi Sufyan (ra) and Khalid (ra) bin Walid etc. met with them. Having stayed in Syria, these chiefs had lost their simplicity. Hence, when they came before Hazrat Umar (ra), he was furious to see them in a state where they were wearing beautiful silk and brocades and were wearing ceremonious dresses and luxury garments, and it seemed from their outward appearance that they were non-Arabs. Hazrat Umar (ra) dismounted his horse, picked up some pebbles and threw them towards them, asking why they had adopted the non-Arab customs so quickly. They said that beneath the dresses were their weapons, i.e. they never gave up their art of fighting. Hazrat Umar (ra) then said, “If this is true, then it is fine that you wore this to display to them, but inside you are still Arabs.”
(Al-Faruq, Shibli Nu‘mani, p. 124, Idarah Islamiyyat, 2004)