Muhammad ibn Abi Umayr from Hammad from Hariz from Zurarah, who said:
Abu Ja‘far عليه السلام said: "Whoever believes in Allah سبحانه وتعالى and the Last Day (Qiyama) should not pass the night without performing Witr."
Ali Akbar al-Ghaffari
Tahdhīb al-Aḥkām fī Sharḥ al-Muqniʿah, vol. 2, p. 366