Abi Osamah said that once he went to say farewell to Imam Sadiq (a.s). He narrated that Imam Sadiq (a.s) said
“Why do you invite the people to follow me? I swear by God that I have not found anyone who would listen to and obey me except for one man, who was Abdullah ibn Abi Ya'fur, may God bless him. He obeyed me and performed what I advised him to do. I swear by God that it is better for you if you keep in your heart what I make you aware of, and do not divulge it. This way you will be nobler since you know what others need and you do not need what the people have. But when you divulge what I order you to keep as a secret you will be humiliated by the people for this act.” Abi Osamah said: “May I be your devoted servant! What happens if one keeps what you tell him a secret and does not tell it to your friends. When they hear it from someone else they will get really upset.” Imam Sadiq (a.s) said: “I swear by God that I what I tell you is right. Tell me what will you tell your brothers and friends who will rush to see you tomorrow when you go to Kufa and ask about what I told you?” Abi Osamah said: “I will only tell them whatever you tell me, no more and no less.” Then Imam Sadiq (a.s) said: “Deliver my greetings to those who listen and obey me. Advise them to fear God and adhere to piety, struggling for God, honesty in speech and trustworthiness, extendig their prostration in prayer, and treating their neighbors with kindness. This is the cause for which the Prophet Muhammad (a.s) was appointed. Therefore you must return whatever you are entrusted with to its owner, whether he is a good person or a bad one, since the Prophet of God (a.s) has stressed that even a borrowed needle with thread should be returned to its owner. Attend and do your prayers in their congregational prayers. Attend their burial ceremonies. Visit them when someone gets ill. Respect their rights. I get pleased when I hear that you are pious, honest, trustworthy, well behaved, and are known to be one of my followers. Then the people will say these are the manners that Imam Sadiq (a.s) has taught. Whenever you act otherwise, I will suffer from the bad consequences. I swear by God that my father told me: “One of the followers of Imam Ali (a.s) who lived in Mecca was the most trustworthy Shiite, and the most honest one. The people used to go to him to leave their goods or their wills for safekeeping. When people asked about him, they would be asked if anyone else could be found like him.” Therefore fear God, be a source of pride, and not a source of infamy for us. Attract all love and friendship towards us, and repel all evil and wrong accusations from us. We are not as we are said to be. There is a certain right established for us in the divine Book, and we are relatives of the Prophet of God (a.s). We are divinely Pure, and are born pure; and no one else can claim to be born pure, and he is a liar if he does so. Remember God often and remember death often. Recite the Quran. Send a lot of blessings for the Prophet since there are ten goods in this act. Remember what I advised you to do. I will trust you to God.”