The Farewell Sermon — what he said when he knew he was leaving
Source: Sahih Muslim 1218 (the Farewell Hajj, narrated by Jabir ibn Abdullah); Sahih al-Bukhari 45, 67, 1739, 4406; Quran 5:3
They left Madinah at the end of Dhul-Qa'dah.
The detail in Jabir's narration is so fine that it reads like a diary: where they stopped, what happened at each stage, who asked what. Ihram was entered at Dhul-Hulayfah. A child was born on the road and a ruling was asked about it.
And then the talbiyah — the call still recited in the same words today:
Here I am, O Allah, here I am. Here I am, You have no partner, here I am. Indeed all praise and favour are Yours, and the dominion. You have no partner.
Sahih Muslim 1218.
Jabir says that as far as the eye could see there were people ahead, behind, to the right and to the left.
Reports differ on the number; over a hundred thousand is the figure usually given. But more than the number, the thing to consider is who they were. Among them were people whose families had once driven him out of his town. Among them were people of Ta'if. And now all of them were in one garment, reciting one sentence, walking one way.