Sayyiduna Anas bin Malik (may Allah be pleased with him) said that in the time of the Messenger of Allah (peace and blessings be upon him), Abu Talhah (may Allah be pleased with him) did not observe (voluntary) fasts because of jihad; but when the Prophet (peace and blessings be upon him) passed away, I never saw him leave off fasting except on the day of Eid al-Adha or Eid al-Fitr.
Hadith Referenceالمعجم الكبير للطبراني / باب الزاي / 4664