Muhammad ibn Ali al-Baqir narrates that, “When my father (Ali ibn al-Hussain) was about to pass away, he held me to his chest and then said, ‘My son, I make my will to you as my father (Hussain ibn Ali) did to me when he was about to pass away and that which his father willed to him.’ He said, ‘My son, beware of oppressing one who has no helper against you but God”.
(Al-Kaafi, vol. 2, pg. 331)