Musnad Ahmad 1012:55

Yahya ibn Sa'id al-Qattan narrated to us, from Yahya ibn Sa'id al-Ansari, who said: 'Ubadah ibn al-Samit: "Abu al-Walid was a Badr-participant, an 'Aqabah-participant, and a Tree-participant (Bay'at al-Ridwan), and he was a leader (naqib)." Yahya ibn Sa'id al-Qattan narrated to us, from Yahya—meaning ibn Sa'id al-Ansari—who said: Muhammad ibn Yahya ibn Habban narrated to me, from Ibn Muhayriz, from a man from Banu Kinanah called al-Mukhaddaji, who said: There was a man in al-Sham called Abu Muhammad. He said: "The Witr prayer is obligatory." He said: So I went to 'Ubadah and said: "Indeed, Abu Muhammad claims that the Witr prayer is obligatory." He said: "Abu Muhammad lied. I heard the Messenger of Allah (ﷺ) say: 'Five prayers which Allah has prescribed upon the servants. Whoever performs them, not losing anything from them out of disregard for them, he comes having a covenant with Allah that He will admit him into Paradise. And whoever loses them out of disregard for them, he comes having no covenant with Him; if He wills, He will punish him, and if He wills, He will admit him into Paradise.'"