Muhammad ibn al-Hasan al-Saffar, from Ahmad ibn Muhammad, from one who narrated it, from al-Halabi, from Abu Abdillah عليه السلام, peace be upon him:
Imam عليه السلام said: “Continuous joining (sawm al-wisal) in fasting is that he makes his dinner his pre-dawn meal (suhur).”
Ali Akbar al-Ghaffari
Tahdhīb al-Aḥkām fī Sharḥ al-Muqniʿah, vol. 4, p. 373