"The messenger of Allah (may Allah's peace and blessings be upon him) used to strive to fast on Mondays and Thursdays. [Ibn Maajah]
"كانَ رسولُ اللهِ -صلى الله عليه وسلم- يَتَحرّى صومَ الإثنينِ والخميسِ. [صحيح.] - [رواه الترمذي"
