Narrated Ammar: Abu Ishaq reported on the authority of Silah: We were with Ammar on the day when the appearance of the moon was doubtful. (The meat of) goat was brought to him. Some people kept aloof from (eating) it. Ammar said: He who keeps fast on this day disobeys Abul Qasim (i. e. the Prophet) ﷺ.
Hadith Referenceسنن ابي داود / كتاب الصيام / 2334
Hadith Gradingالألبانی:صحيح | زبیر علی زئی:ضعيف, إسناده ضعيف, ترمذي (686) نسائي (2190) ابن ماجه (1645), أبو إسحاق مدلس وعنعن, وللحديث شواهد ضعيفة, انوار الصحيفه، صفحه نمبر 87