1- مُحَمَّدُ بْنُ يَحْيَى عَنْ أَحْمَدَ بْنِ مُحَمَّدٍ عَنِ ابْنِ فَضَّالٍ عَنْ إِبْرَاهِيمَ بْنِ مُسْلِمٍ الْحُلْوَانِيِّ عَنْ أَبِي إِسْمَاعِيلَ الصَّيْقَلِ الرَّازِيِّ عَنْ أَبِي عَبْدِ اللَّهِ ع قَالَ: إِنَّ فِي الْجَنَّةِ لَشَجَرَةً تُسَمَّى الْمُزْنَ فَإِذَا أَرَادَ اللَّهُ أَنْ يَخْلُقَ مُؤْمِناً أَقْطَرَ مِنْهَا قَطْرَةً فَلَا تُصِيبُ بَقْلَةً وَ لَا ثَمَرَةً أَكَلَ مِنْهَا مُؤْمِنٌ أَوْ كَافِرٌ إِلَّا أَخْرَجَ اللَّهُ عَزَّ وَ جَلَّ مِنْ صُلْبِهِ مُؤْمِناً.
(It has been narrated) from Imam Abu Abdillah, Imam al-Sadeq (peace be upon him) having said: “In paradise, there is a tree called al-Muzn (Nimbus). When Allah wants to create a believer, He makes a drop to drip from it. It then falls on a vegetable or a fruit that either a believer or unbeliever then consumes for food but Allah, the Most Majestic, the Most Glorious, brings out a believer from his back.”
Reference: al-Kafi, volume 2, page 14, tradition no. 1
Notes:
This tradition states how a believer can be born, regardless of whether the parents are practicing Muslims or not.
It is for the same reason one can cite countless historical examples of believers born into non-Muslim families and vice versa.
This is one way Allah, the Mighty and Majestic, demonstrates His power by accomplishing His will in unexpected ways.