Narrated by the Shaykh (Al-Mufid), may Allah سبحانه وتعالى support him, from Ahmad ibn Muhammad, from his father, from Muhammad ibn Yahya and Ahmad ibn Idris, from Muhammad ibn Ahmad ibn Yahya, from Ali ibn Isma'il, from Hammad ibn Isa, from Hariz, from Abu Abdullah عليه السلام, who said: Imam عليه السلام said: "Whoever performs ghusl for janabah (major ritual impurity) and does not wash his head, and then decides to wash his head afterward, must necessarily repeat the ghusl."