The Fall of Khaibar and the Flag of Islam
Buraidah al-Aslami narrates that when the Holy Prophet (sa) reached the battlefield of Khaybar, he handed the flag to Hazrat Umar bin al-Khattab (ra).
(Al-Tabaqaat-ul-Kubra li ibn Saad, Vol. 3, p. 206, Dar-ul-Kutub al-Ilmiyyah, Beirut, 2012) (Furhang-e-Sirat, p. 75, Zawar Academy, Karachi, 2003)