Marking and garlanding (the Hadi) at Dhul-Hulaifa and then assuming Ihram Sahih al-Bukhari 1694, 1695
Translation
Narrated Al-Miswar bin Makhrama and Marwan
The Prophet (ﷺ) set out from Medina with over one thousand of his companions (at the time of the Treaty of Hudaibiya) and when they reached Dhul-Hulaifa, the Prophet (ﷺ) garlanded his Hadi and marked it and assumed Ihram for `Umra.