Muwatta Malik 268

Yahya related to me from Malik from Yahya ibn Said from Muhammad ibn Yahya ibn Habban from Ibn Muhayriz that a man from the Kinana tribe called al-Mukhdaji heard a man in Syria known as Abu Muhammad saying, "The witr is obligatory (fard)." Al-Mukhdaji said, "I went to Ubada ibn as-Samit and presented myself to him as he was going to the mosque, and told him what Abu Muhammad had said. Ubada said that Abu Muhammad had lied and that he had heard the Messenger of Allah, (ﷺ), say, 'Allah the Majestic and Mighty has written five prayers for mankind, and whoever does them and does not waste anything of them by making light of what is due to them, there is a pact for him with Allah that He will admit him into the Garden.Whoever does not do them, there is no pact for him with Allah. If He wishes, He punishes him, and if He wishes, He admits him into the Garden.' "