It is narrated from Sayyiduna Ya'la (may Allah be pleased with him) that a man came to the Prophet (peace and blessings be upon him) while he was at al-Ji'ranah. The man was wearing a cloak (jubbah) and on it was a trace of khaluq (perfume) - Hammam said: or perhaps he said: a trace of yellow - and he said: "What do you command me to do in my Umrah?" He said: And revelation was sent down upon the Prophet (peace and blessings be upon him), so he was covered with a cloth. He said: And Ya'la used to say: I wished that I could see the Messenger of Allah (peace and blessings be upon him) at the time revelation was coming down upon him. So Umar (may Allah be pleased with him) said to me: "Would you like to look at the Messenger of Allah (peace and blessings be upon him) while revelation has come down upon him?" He said: Umar (may Allah be pleased with him) lifted the edge of the cloth, and I looked at him, and he (peace and blessings be upon him) was making a heavy snoring sound (heavy breathing). Hammam said: I think the narrator also said that this snoring was like that of a young camel. Then, when that state left him (peace and blessings be upon him), he said: "Where is the one who asked about Umrah? Take off the cloak and wash off from yourself" - the narrator sometimes said "the trace of khaluq" and sometimes said "the trace of yellow"; Hammam was in doubt about it - "and do in your Umrah what you would do in your Hajj."
Hadith Referenceالمعجم الكبير للطبراني / باب الياء / 18873