It is narrated from Hazrat Anas (may Allah be pleased with him) that Hazrat Abu Talha (may Allah be pleased with him) did not keep many voluntary fasts during the blessed lifetime of the Prophet (peace and blessings be upon him), but after the Prophet’s (peace and blessings be upon him) passing, he would not leave fasting in any circumstance except for travel or illness.
Hadith Referenceمسند احمد / مسند المكثرين من الصحابة / 12016
Hadith Gradingحکم دارالسلام:إسناده صحيح، وفي البخاري: 2828: (كان أبو طلحه لا يصوم على عهد النبى ﷺ من اجل الغزو، فلما قبض النبى ﷺ لم أره مفطرا الا يوم فطر أو أضحي)