Imam Reza (A.S) On the Resurrection Day three groups of people are closest to Allah until the end of the Reckoning: Those who quench their anger and do not oppress others when they have power, those mediate between two people and do not favor either side in the least amount, and those who tell the truth whether it be in their favor or not. (Mishkat-ul-Anwar, Section Eight, Chp. 1)
The Holy Prophet [s.a] said: ‘Someone who possesses knowledge on a subject but conceals it when he is asked will be bridled with reins of fire.’ (Therefore, if a person possesses information that would help a bewildered person and improve his situation but he remains silent, he has surely committed a great sin.)
Source: Al -'Ithna-'Ashariyyah, p. 11