Volume 4, Book 54, Number 419:
Narrated Abu Bakra:
The Prophet said. “(The division of time has turned to its original form which was current when
Allah created the Heavens and the Earths. The year is of twelve months, out of which four months
are sacred: Three are in succession Dhul-Qa’ da, Dhul-Hijja and Muharram, and (the fourth is) Ra –
jab of (the tribe of) Mudar which comes between Jumadi-ath-Thaniyah and Sha ban.”