It was narrated from 'Abdullah bin 'Utbah bin Mas'ud that a man came to the Prophet and said:"I have given a gift to my son, so bear witness." He said: "Do you have any other children?" He said: "Yes." He said: "Have you given them something like that which you have given him?" He said: "No." He said: "Shall I bear witness to unfairness?

English translation · Sunan an-Nasa'i