Al-Aḥzāb 33:40: ما کان محمد أبا أحد من رجالکم و لکن رسول الله و خاتم النبیین و کان الله بکل شیء علیما
Muḥammad (peace be upon him and his family) is not the father of any of your men; rather, he is the Messenger of God and the Seal of the Prophets. God has knowledge of all things.
This noble verse was revealed to overturn a rule from the pre-Islamic era, when an adopted child was treated like a biological child—a custom that gave rise to particular social and ethical problems. This is made clear in verse 37 of Sūrat al-Aḥzāb:
Al-Aḥzāb 33:37: و إذ تقول للذی أنعم الله علیه و أنعمت علیه أمسک علیک زوجک و اتق الله و تخفی فی نفسک ما الله مبدیه و تخشى الناس و الله أحق أن تخشاه فلما قضى زید منها وطرا زوجناکها لکی لا یکون على المؤمنین حرج فی أزواج أدعیائهم إذا قضوا منهن وطرا و کان أمر الله مفعولا
And remember when you said to the one whom God had favoured, and whom you too had favoured [your adopted son, Zayd], “Keep your wife and be mindful of God.” You kept repeating this, while concealing in your heart what God would bring to light; and you feared people, though God is more worthy that you should fear Him. Then, when Zayd had fulfilled his desire with her and parted from her, We gave her to you in marriage, so that believers would have no difficulty marrying the former wives of their adopted sons after they had divorced them. God’s command was bound to be carried out (and the mistaken custom forbidding such marriages had to be abolished).
The same matter is further clarified in verse 4 of Sūrat al-Aḥzāb:
Al-Aḥzāb 33:4: ما جعل الله لرجل من قلبین فی جوفه و ما جعل أزواجکم اللائی تظاهرون منهن أمهاتکم و ما جعل أدعیاءکم أبناءکم ذلکم قولکم بأفواهکم و الله یقول الحق و هو یهدی السبیل
God has not placed two hearts within any man; nor has He made your wives whom you declare to be as forbidden to you as your mothers into your mothers; nor has He made your adopted sons into your sons. These are merely words you utter. God speaks the truth and guides to the right path.
And now, the blessed hadith:
قال علی بن أبی طالب ع: سمعت رسول الله ص یقول أنا و علی أبوا هذه الأمه، و لحقنا علیهم أعظم من حق أبوی ولادتهم، فإنا ننقذهم- إن أطاعونا- من النار إلى دار القرار، و نلحقهم من العبودیه بخیار الأحرار
“Ali and I are the two fathers of this community. Our right over its people is greater than the right of their biological parents, for if they obey us, we will save them from Hell and lead them to the everlasting abode; we will free them from servitude and grant them the dignity of the free.”
The Prophet of Islam (peace be upon him and his family) is the root and source of the tree of human life. The world of existence and all who dwell within it are like the leaves of this tree. In other words, he is the father of bodily, spiritual and innermost life.