Mishkat al-Masabih
He reported God’s messenger as saying, “There are angels on the mountain roads of Medina, so neither plague nor the dajjal can enter it.” Bukhari and Muslim.
وَعَنْهُ قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «عَلَى أَنْقَابِ الْمَدِينَةِ مَلَائِكَةٌ لَا يَدْخُلُهَا الطَّاعُونُ وَلَا الدَّجَّالُ»
Reference