مُسْنَدُ أَحْمَدَ
Musnad Ahmad 1854
Musnad of 'Abdullah bin al-'Abbas bin 'Abdul-Muttalib from the Prophet
It was narrated from Ibn "Abbas that the Messenger of Allah (ﷺ) marked his sacrificial animal with a cut on its right side, then he wiped the blood from it, and he garlanded it with two sandals."
Musnad Ahmad 1855Sahih (Darussalam) [ Muslim (1243)]