The Book of Pilgrimage
حَدَّثَنَا يَحْيَى بْنُ يَحْيَى، قَالَ قَرَأْتُ عَلَى مَالِكٍ عَنْ نُعَيْمِ بْنِ عَبْدِ اللَّهِ، عَنْ أَبِي هُرَيْرَةَ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " عَلَى أَنْقَابِ الْمَدِينَةِ مَلاَئِكَةٌ لاَ يَدْخُلُهَا الطَّاعُونُ وَلاَ الدَّجَّالُ " .Abu Huraira (Allah be pleased with him) reported Allah's Messenger (ﷺ) as saying:There are at the approaches of Medina angels so that plague and the Dajjal shall not penetrate into it
From Sahih Muslim, whose reports the scholars accept as authentic.