The Prophet ﷺ said, "The Hour will not come until nearly thirty lying impostors are sent, each one claiming to be a messenger of Allah."
حدثنا عبد الرحمن بن مهدي عن مالك عن أبي الزناد عن الأعرج
عن النبي ﷺ قال لا تقوم الساعة حتى يبعث دجالون كذابون قريب من ثلاثين كلهم يزعم أنه رسول الله
Its isnad is sahih, though it was not mentioned in Muwatta. So it is among what Malik related outside the Muwatta, or from the Muwatta but not through the transmission of Yahya bin Yahya Andalusi, the transmitter of the printed Muwatta.Muslim related it, 2:372, from Zuhayr bin Harb and Ishaq bin Mansur, both of them from Abdul-Rahman bin Mahdi, with this same isnad.Bukhari related it, within a lengthy hadith, 6:72-78, through the route of Shuayb from Abu Zinad from Abdul-Rahman, who is Araj, from Abu Hurairah.He also related it, together with another hadith, 13:454, through the route of Abdul-Razzaq from Mamar from Hammam bin Munabbih from Abu Hurairah.See also what has already passed in the Musnad of Abdullah bin Umar bin Khattab, 5694, 5695, 5808, 5985.