Musnad Ahmad 937:154

Bishr ibn al-Mufaddal narrated to us, from Khalid ibn Dhakwan, Ayyub ibn Bashir narrated to me, from so-and-so al-Anazi—and he did not say: al-Ghubari—that he came with Abu Dharr. When he returned, the people dispersed from him, so I said: "O Abu Dharr, I am going to ask you about some of the affairs of the Messenger of Allah, may Allah bless him and grant him peace." He said: "If it is a secret from the secrets of the Messenger of Allah, may Allah bless him and grant him peace, I will not tell it to you." I said: "It is not a secret, but was it the case that when he met a man, he would take his hand and shake it?" He said: "You have fallen upon one who is well-informed. He never met me once without taking my hand, except for one time, and that was the last of them. He sent for me, and I came to him during his illness in which he passed away. I found him lying down, so I leaned over him, and he raised his hand and embraced me, may Allah bless him and grant him peace."