Yahya bin Habban narrates from Ibn Muhayriz that a man of Kinanah who was called al-Mukhdaji heard a man in Syria, who was called Abu Muhammad, saying that the witr is obligatory. Al-Mukhdaji says: I went to Ubadah bin al-Samit (may Allah be pleased with him) and informed him. Sayyiduna Ubadah (may Allah be pleased with him) said: Abu Muhammad has made a mistake, for I heard the Messenger of Allah (peace and blessings be upon him); he (peace and blessings be upon him) said: "Allah Almighty has made five prayers obligatory upon His servants. Whoever does not waste them out of belittling them, Allah will admit him into Paradise. And whoever does not offer these prayers has no promise from Allah; if He wills, He will punish him, and if He wills, He will admit him into Paradise."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الشهادات / 20972