Quran and Sunnah is Sufficient

During the Khilaafat of Sayyidina Abu Bakr (Radiallahu anhu) the Muslims met the Romans (of the Byzantium Empire) in battle. The Muslims defeated them and reckoning that such was the custom of the enemy, decided to do the same to them. Hence they cut off the head of the commander and sent it with Sayyidina Uqbah bin Aamir (Radiallahu anhu) to Sayyidina Abu Bakr (Radiallahu anhu) in Medina.

When the messenger came to him with the severed head, Sayyidina Abu Bakr (Radiallahu anhu) showed intense displeasure. Seeing this Sayyidina Uqbah (Radiallahu anhu) exclaimed: “0 Successor of Rasulullah (Sallallahu Alayhi Wasallam) (why this displeasure?) These people will do the same thing to us.”

Sayyidina Abu Bakr (Radiallahu anhu) replied:

“What? Will the practices and actions of the people of Persia and Byzantium be followed? Never should the head of anyone be brought before me. For us the Book of Allah and the Sunnah of Rasulullah (Sallallahu Alayhi Wasallam) is sufficient to be followed.”

(Quoted from Shara—ul—Siyar vol.1)