Why was Sayyiduna Khalid ibn Walid (radiyallahu ‘anhu) known as Sayfullah?
It was Nabi (sallallahu ‘alayhi wa sallam) who conferred upon him the title; sayfullah (the sword of Allah) on the day of the battle of Mutah. The commentators of hadith say since that day he is known as sayfullah.
(Sahih Bukhari, Hadith: 4262, Fathul Bari and ‘Umdatul Qari)
And Allah Ta’ala Knows best
Answered by: Moulana Suhail Motala
Approved by: Moulana Muhammad Abasoomar
Checked by: Moulana Haroon Abasoomar
This answer was collected from HadithAnswers.com. The answers were either answered or checked by Moulana Haroon Abasoomar (rahimahullah) who was a Shaykhul Hadith in South Africa, or by his son, Moulana Muhammad Abasoomer (hafizahullah), who is a Hadith specialist.