Narrated Abu Sa`id Al-Khudri:

A man heard another man reciting (in the prayers): 'Say (O Muhammad): "He is Allah, the One." (112.1) And he recited it repeatedly. When it was morning, he went to the Prophet (ﷺ) and informed him about that as if he considered that the recitation of that Sura by itself was not enough. Allah's Messenger (ﷺ) said, "By Him in Whose Hand my life is, it is equal to one-third of the Qur'an."

Narrated `Aisha:

The Prophet (ﷺ) sent (an army unit) under the command of a man who used to lead his companions in the prayers and would finish his recitation with (the Sura 112): 'Say (O Muhammad): "He is Allah, the One." ' (112.1) When they returned (from the battle), they mentioned that to the Prophet. He said (to them), "Ask him why he does so." They asked him and he said, "I do so because it mentions the qualities of the Beneficent and I love to recite it (in my prayer)." The Prophet; said (to them), "Tell him that Allah loves him."

Narrated Abu Sa`id Al-Khudri:

A man heard another man reciting: Surat-ul-Ikhlas (The Unity) 'Say: He is Allah, the One (112) and he was repeating it. The next morning he came to Allah's Messenger (ﷺ) and mentioned the whole story to him as if he regarded the recitation of that Sura as insufficient On that, Allah's Messenger (ﷺ) said, "By Him in Whose Hand my soul is! That (Sura No. 112) equals one-third of the Qur'an."

Narrated Abu Said Al-Khudri:

A man heard another man reciting (Surat-Al-Ikhlas) 'Say He is Allah, (the) One.' (112. 1) repeatedly. The next morning he came to Allah's Messenger (ﷺ) and informed him about it as if he thought that it was not enough to recite. On that Allah's Messenger (ﷺ) said, "By Him in Whose Hand my life is, this Surah is equal to one-third of the Qur'an!"