Muwatta 850

A saying of Malik: a man should not enter into any of the righteous acts that people undertake voluntarily and then break it, until he completes it in its manner: if he begins the prayer he should not turn away until he has prayed two rak'as; if he fasts he should not break his fast until he completes his day's fast; if he enters into the pilgrimage he should not return until he completes his pilgrimage; and if he begins the circumambulation he should not stop it until he completes its seven rounds. Malik cites the words of God: then complete the fast until the night (Al-Baqara Al-Baqara 187), and the words: complete the pilgrimage and the visit for God (Al-Baqara Al-Baqara 196). He says: if a man enters the pilgrimage voluntarily, having already fulfilled the obligatory one, he may not abandon the pilgrimage after entering it and return unrestricted from the road. The editor notes that Abu Musab transmitted it from Malik (831). ¹

Belongs to the Muwatta, Book of Fasting. Source: the Muwatta. Mentions Malik ibn Anas. Built on in the chapters on voluntary fasting (sawm tatawwu), the pilgrimage (hajj) and prayer (salah).