Ibrahim said: In our recitation, concerning the expiation of an oath, it has come: fasting for three consecutive days.
(b) Ibn Mas'ud (may Allah be pleased with him) used to recite: Fasting for three consecutive days. All of these are mursal reports from Abdullah bin Mas'ud (may Allah be pleased with him).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الأيمان / 20012