Sayyiduna al-Nu'man bin Bashir (may Allah be pleased with them both) said: My father gave me a gift (in Isma'il's narration: he gifted him a slave). So my mother, Amrah bint Rawahah (may Allah be pleased with her), said to him: "Go to the Messenger of Allah (peace and blessings be upon him) and make him a witness to it." So he came to the Messenger of Allah (peace and blessings be upon him), mentioned this to him and said: "I have given my son al-Nu'man a gift, and Amrah has asked me to make you a witness to it." He (peace and blessings be upon him) said: "Do you have other children besides him?" I said: "Yes." He said: "Have you given all of them the like of what you gave al-Nu'man?" He said: "No." Then some of the narrators said: He (peace and blessings be upon him) said: "This is injustice." And some of them said: He (peace and blessings be upon him) said: "This is a talji'ah (that is, a mere sham arrangement); make someone other than me a witness to this." Mughirah said: He (peace and blessings be upon him) said: "Would it not please you that they all be equal toward you in dutifulness and kindness?" He said: "Yes." He said: "Then make someone other than me a witness to this." Mujalid added in his narration: "They have the right over you that you treat them justly, just as you have the right over them that they be dutiful to you."
Hadith Referenceالمعجم الكبير للطبراني / مسند النساء / 21215