The Prophet ﷺ said, "Whoever memorizes the first ten verses of Surah al-Kahf will be protected from the Dajjal."
حدثنا يزيد أنا همام بن يحيى عن قتادة عن سالم بن أبي الجعد عن معدان بن أبي طلحة
عن النبي ﷺ قال من حفظ عشر آيات من أول سورة الكهف عصم من الدجال
Its chain of transmission is sahih, and its narrators are well-known and reliable. The hadith was narrated by Muslim, 1/555, no. 809, in the chapter on travelers, on the merit of Surah Kahf and the Verse of the Throne, and by Abu Dawud, 4/115, no. 4323, and by Baghawi in Sharh al-Sunnah, 4/469, no. 1204, and by Hakim, 2/368, who graded it sahih and was followed in this by Dhahabi, and by Bayhaqi, 3/249.