Sunan Abi Dawud — Fasting (Kitab Al-Siyam) — Hadith No: 2426
Translation
The tradition mentioned above has also been transmitted by Abu Qatadah through a different chain of narrators. This version add:He said: Messenger of Allah, tell me about keeping fast on Monday and Thursday. He said: On it I was born, and on it the Qur'an was first revealed to me