الكافي 1/4/73/12

12. Al-Husayn ibn Muhammad has narrated from Muhammad ibn Ahmad al-Nahdi from Muhammad ibn Khallad al-Sayqal from Muhammad ibn al-Hassan ibn ‘Ammar who has said the following: “Once I was in a meeting with Ali ibn Ja‘far ibn Muhammad in Medina, - I stayed with him for two years to write from him what he would hear from his brother, Abu al-Hassan عليه السلام ,- at such time Abu Ja‘far Muhammad ibn Ali al-Rida عليه السلام came in the mosque, the mosque of the Messenger of Allah. Ali ibn Ja‘far rushed towards him bare foot and without his gown. He kissed his hand and showed great respect for him. Abu Ja‘far said to him, “Uncle, please sit down, may Allah grant you well being.” He said, “My master, how can I sit when you are standing.” When Ali ibn Ja‘far returned to his place his companions began to blame him saying, “You are the uncle of his father, how can you act as such before him?” He said to them, “Be quite, When Allah, the Most Majestic, the Most gracious, has not qualified this beard –holding his beard in his hand- but has qualified this young man and has given him such position, should I deny his excellence and virtue? I seek refuge before Allah from what you say. In fact, I am a servant for him.”