عن علي يعني ابن أبي طالب قال : سمعت رسول الله صلى الله عليه وسلم يقول : المستشار مؤتمن فإذا استشير فليشر بما هو صانع لنفسه (مجمع الزوائد #13159)

Hazrat ‘Ali bin Abi Taalib (radhiyallahu ‘anhu) reports that Rasulullah (sallallahu ‘alaihi wasallam) said, “The person whose mashwarah (advice) is sought is entrusted (with the trust of advising correctly). Hence, when his advice is sought by anyone, he should advise that person with that which he regards best for himself (i.e. he should advise the person according to what he regards best for the person, just as he would choose the best for himself).”