Abu Hurairah reported,

The Messenger of Allah ﷺ said, Allah says, "The son of Adam has called Me a liar, though he has no right to do so, and he has insulted Me, though he has no right to do so. His calling Me a liar is his saying that I will never bring him back as I first created him. His insulting Me is his saying that Allah has taken a son, while I am the Eternally Self-Sufficient, who has not begotten and was not begotten, and there is none comparable to Me, 'He neither begets nor was He begotten, and there is none comparable to Him'" [Ikhlas 112:3–4].The words kufuwan, kufayan, and kifaan all carry the same meaning.

عن أبي هريرة قال

قال رسول الله ﷺ: كذبني ابن آدم ولم يكن له ذلك، وشتمني ولم يكن له ذلك. أما تكذيبه إياي أن يقول: إني لن أعيده كما بدأته، وأما شتمه إياي أن يقول: اتخذ الله ولدا، وأنا الصمد الذي لم ألد ولم أولد، ولم يكن لي كفوا أحد، {لم يلد ولم يولد ولم يكن له كفوا أحد} [سورة الإخلاص]. كفوا وكفيئا وكفاء واحد.