It is narrated from Imam Ridha/Reza (AS) who said:

A person is not a believer unless these three characteristics are in him/her: A characteristic from God, a characteristic from his/her Prophet (PBUH), and a characteristic from his/her Imam (AS). The characteristic from God is keeping secrets, and Allah (SWT) said: “Only God has the knowledge of the unseen, and God does not inform anyone about it except the Prophet whom God is satisfied with him.” And the characteristic which must have from the Prophet (PBUH) is to have good behaviour with people, because God commanded the Prophet (PBUH) to have good behaviour towards people and said: “Choose the path of forgiveness and order to good behaviour”, and the characteristic from Imam (AS) is having patience in difficulty and hardship [1].

[1] Alhukmal Zahirah, Translated by Ansari, Page 460.

Source: en.shafaqna.com