SHAFAQNA – It is narrated from Imam Sajjad (AS) who said: The most grateful of you to God is the most grateful of you to People. On the Day of Judgment, Allah (SWT) will say to God’s servant: Did you thank such a person? And he will reply: O’ God, I thanked Allah (SWT). God will say: Because you have not thanked such a person, you have not thanked God .
In “A divine perspective on rights”, Imam Sajjad (AS) said: The right of a person who does good to you is that you thank him and talk about that good deed and remember him in a good way as well as pray for him sincerely. If you do so, without a doubt you have been grateful to him in private and in public. In addition if one day you are able to reciprocate (that good deed), try to do so .
 Osul Kafi, Vol. 3, page 156.
 Tohaful Oqool, Page 271.