Al Ahzab Ayah 5

ٱدْعُوهُمْ لِأَبَآئِهِمْ هُوَ أَقْسَطُ عِندَ ٱللَّهِ‌ۚ فَإِن لَّمْ تَعْلَمُوٓاْ ءَابَآءَهُمْ فَإِخْوَٲنُكُمْ فِى ٱلدِّينِ وَمَوَٲلِيكُمْ‌ۚ وَلَيْسَ عَلَيْكُمْ جُنَاحٌ فِيمَآ أَخْطَأْتُم بِهِۦ وَلَـٰكِن مَّا تَعَمَّدَتْ قُلُوبُكُمْ‌ۚ وَكَانَ ٱللَّهُ غَفُورًا رَّحِيمًا ٥ Let your adopted children keep their family names. That is more just in the sight of Allah. But if you do not know their fathers, then they are ?simply? your fellow believers and close associates. There is no blame on you for what you do by mistake, but ?only? for what you do intentionally. And Allah is All-Forgiving, Most Merciful.