He reported God’s messenger as saying, “Is any of you incapable of reciting a third of the Qur’ān in a night?” On being asked how they could recite a third of the Qur’ān he replied. “‘Say, He is God, One’ (Qur’ān, 112) is equivalent to a third of the Qur’ān.”
Muslim transmitted it, and Bukhārī transmitted it from Abū Sa'īd.
وَعَنْ أَبِي الدَّرْدَاءِ قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «مَنْ حَفِظَ عشر آيَات من أول سُورَة الْكَهْف عصم من فتْنَة الدَّجَّال» . رَوَاهُ مُسلم
Abūd Dardā’ reported God’s messenger as saying, “If anyone learns by heart ten verses at the beginning of sūra al-Kahf (Qur’ān, 18) he will be protected from the dajjal.”
‘Ā’isha said that the Prophet sent a man in charge of an expedition and he would recite for his companions during their prayer, finishing with “Say, He is God, One.” When they returned they mentioned that to the Prophet, and he told them to ask him why he did that. They asked him and he replied, “Because it is a description of the Compassionate One, and I like to recite it.” Then the Prophet said, “Tell him that God loves him.”
Abū Mas'ūd reported God’s messenger as saying, “If anyone recites the two verses at the end of sūra al-Baqara at night they will avert harm from him.” *Or will be enough for him.