The Messenger of Allah ﷺ mentioned the Dajjal (Antichrist) saying, “If he comes forth while I am among you I shall be the one who will dispute with him on your behalf, but if he comes forth when I am not among you, a man must dispute on his own behalf, and Allah will take my place in looking after every Muslim. Those of you who live up to his time should recite over him the opening verses of Sūrah al-Kahf, for they are your protection from his trial.” We asked, “How long will he remain on the earth?” He replied, “Forty days, one like a year, one like a month, one like a week, and rest of his days like yours.” We asked, “Messenger of Allah ﷺ, will one day’s prayer suffice us in this day which will be like a year?” He replied, “No, you must make an estimate of its extent. Then Jesus son of Mary will descend at the white minaret to the east of Damascus. He will then catch him up at the gate of Ludd and kill him.” Reference:
Sunan ad-Darimi 4321; A more detailed narration is found in Sahih Muslim 2937
عَنِ النَّوَّاسِ بْنِ سَمْعَانَ الْكِلاَبِيِّ، قَالَ ذَكَرَ رَسُولُ اللَّهِ صلى الله عليه وسلم الدَّجَّالَ فَقَالَ " إِنْ يَخْرُجْ وَأَنَا فِيكُمْ فَأَنَا حَجِيجُهُ دُونَكُمْ وَإِنْ يَخْرُجْ وَلَسْتُ فِيكُمْ فَامْرُؤٌ حَجِيجُ نَفْسِهِ وَاللَّهُ خَلِيفَتِي عَلَى كُلِّ مُسْلِمٍ فَمَنْ أَدْرَكَهُ مِنْكُمْ فَلْيَقْرَأْ عَلَيْهِ فَوَاتِحَ سُورَةِ الْكَهْفِ فَإِنَّهَا جِوَارُكُمْ مِنْ فِتْنَتِهِ " . قُلْنَا وَمَا لُبْثُهُ فِي الأَرْضِ قَالَ " أَرْبَعُونَ يَوْمًا يَوْمٌ كَسَنَةٍ وَيَوْمٌ كَشَهْرٍ وَيَوْمٌ كَجُمُعَةٍ وَسَائِرُ أَيَّامِهِ كَأَيَّامِكُمْ " . فَقُلْنَا يَا رَسُولَ اللَّهِ هَذَا الْيَوْمُ الَّذِي كَسَنَةٍ أَتَكْفِينَا فِيهِ صَلاَةُ يَوْمٍ وَلَيْلَةٍ قَالَ " لاَ اقْدُرُوا لَهُ قَدْرَهُ ثُمَّ يَنْزِلُ عِيسَى ابْنُ مَرْيَمَ عِنْدَ الْمَنَارَةِ الْبَيْضَاءِ شَرْقِيَّ دِمَشْقَ فَيُدْرِكُهُ عِنْدَ بَابِ لُدٍّ فَيَقْتُلُهُ.