Mujahid bin Jabir مجاهد بن جبر · The Book on Hajj

The Prophet was asked about whether Umrah was obligatory? He said: "No. But if you perform Umrah it is more virtuous."

Ibn Umar was asked: In which month did the Messenger of Allah perform Umrah? He said: 'During Rajab.' So Aishah said: 'The Messenger of Allah did not perform Umrah except that he was with him - meaning Ibn Umar - and he did not ever perform Umrah in the month of Rajab.'"

"We were with the Messenger of Allah on a journey when he saw a man fall from his camel, his neck was broken and he died, and he was a Muhrim. So the Messenger of Allah said: 'Wash him with water and Sidr, and shroud him in his garments, and do not cover his head. For indeed he will be resurrected on the Day of Judgment saying the Talbiyah.'"