The Messenger of Allah (ﷺ) said, "By Him in Whose Hand my soul is, it is equivalent to one-third of the Qur'an."

According to another version, he (ﷺ) said to his Companions, "Is anyone of you incapable of reciting one-third of the Qur'an in one night?" They considered it burdensome and said: "O Messenger of Allah, which of us can afford to do that?" He (ﷺ) said, "Surat Al-Ikhlas

[Say: He is Allah (the) One] is equivalent to one-third of the Qur'an."

[Al- Bukhari].