´It was narrated that 'Aishah said:` "The Messenger of Allah used to fast until we said: 'He does not want to break his fast.' And he used not to fast until we said: 'He does not want to fast."'
Hadith Referenceسنن نسائي / كتاب الصيام / 2349
Hadith Gradingالألبانی:صحيح الإسناد | زبیر علی زئی:إسناده حسن