The Prophet ﷺ said, "Praying in congregation is superior to a man praying alone by twenty-five prayers, each one equal to his prayer."Affan said, "It has reached me that Abu al-Awwam corroborated this."
حدثنا أبو داود وعفان قالا حدثنا همام عن قتادة عن مورق العجلي عن أبي الأحوص
عن النبي ﷺ قال صلاة الجميع تفضل صلاة الرجل وحده خمسا وعشرين صلاة كلها مثل صلاته قال عفان بلغني أن أبا العوام وافقه
Its isnad is sahih. It has already appeared as 4159 with a similar isnad, and it has already appeared as 3567 by way of Saeed from Qatada from Abu Ahwas, without mentioning Murawaq Ajli between Qatada and Abu Ahwas, like the isnad that follows after this one. It appears that Qatada heard it from Murawaq from Abu Ahwas, and also from Abu Ahwas himself, so he transmitted it both ways.