«مَنْ حَفِظَ عَشْرَ آيَاتٍ مِنْ أَوَّلِ سُورَةِ الْكَهْفِ عُصِمَ مِنَ الدَّجَّالِ»، وَالْاسْتِعَاذَةُ بِاللَّهِ مِنْ فِتْنَتِهِ عَقِبَ التَّشَهُّدِ الْأَخِيرِ مِنْ كُلِّ صَلاَةٍ.
Whoever memorizes ten 'Ayat (Verses) from the beginning of Surat Al-Kahf, will be protected from the False Messiah 1 if he recites in every prayer after the final Tashahhud before ending the prayer, seeking the protection of Allah from the trials of the False Messiah.
Source1 Muslim 1/555, another version mentions the last ten 'Ayat, Muslim 1/556. 2 See invocations no. 55 and 56 of this book.