(V.112:1) See Tauhîd in the Glossary (Appendix).

(V.112:3) A) Narrated Mu‘âdh bin Jabal رضي الله عنه: The Prophet صلى الله عليه وسلم said, "O Mu‘âdh! Do you know what Allâh’s Right upon His slaves is?" I said, "Allâh and His Messenger know better." The Prophet صلى الله عليه وسلم said, "To worship Him (Allâh) Alone and to join none in worship with Him (Allâh). Do you know what their right upon Him is?" I replied, "Allâh and His Messenger know better." The Prophet صلى الله عليه وسلم said, "Not to punish them (if they did so)." [Sahih Al-Bukhari, Vol.9, Hadith No.470]. B) Narrated Abu Sa‘îd Al-Khudrî رضي الله عنه: A man heard another man reciting: ‘Say (O Muhammad): "He is Allâh, (the) One." (112:1) And he recited it repeatedly. When it was morning, he went to the Prophet صلى الله عليه وسلم and informed him about that as if he considered that the recitation of that Sûrah by itself was not enough. Allâh’s Messenger صلى الله عليه وسلم said, "By Him in Whose Hand my soul is, it is equal to one-third of the Our’ân." [Sahih Al-Bukhari, Vol.9, Hadith No.471]. C) Narrated ‘Âishah رضي الله عنها: The Prophet صلى الله عليه وسلم 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 Sûrah 112): ‘Say (O Muhammad): "He is Allâh, (the) One.’" (112:1). When they returned (from the battle), they mentioned that to the Prophet صلى الله عليه وسلم. 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 Most Gracious and I love to recite it (in my prayer)." The Prophet صلى الله عليه وسلم said (to them). "Tell him that Allâh loves him." [Sahih Al Bukhari, Vol.9, Hadith No. 472].