Hadith

 حَدَّثَنَا اَلْحَسَنُ بْنُ أَحْمَدَ رَحِمَهُ اَللَّهُ عَنِ اَلْمُفَضَّلِ قَالَ قَالَ أَبُو عَبْدِ اَللَّهِ ع إِنَّ اَللَّهَ تَبَارَكَ وَ تَعَالَى خَلَقَ اَلْمُؤْمِنِينَ مِنْ أَصْلٍ وَاحِدٍ لاَ يَدْخُلُ فِيهِمْ دَاخِلٌ وَ لاَ يَخْرُجُ مِنْهُمْ خَارِجٌ مَثَلُهُمْ وَ اَللَّهِ مَثَلُ اَلرَّأْسِ فِي اَلْجَسَدِ وَ مَثَلُ اَلْأَصَابِعِ‌ فِي اَلْكَفِّ فَمَنْ رَأَيْتُمْ يُخَالِفُ ذَلِكَ فَاشْهَدُوا عَلَيْهِ بَتَاتاً أَنَّهُ مُنَافِقٌ.

 Al-Hasan bin Ahmed, Allah may have mercy upon him, narrated from… al-Mufaddhal that Abu Abdullah (a) said: Allah, Blessed and Exalted is He, has created all the believers from the same origin. No one is added to them and no one of them is excluded. By Allah (I swear), they are like a head for a body and fingers for a hand. If you notice anyone unlike this description, you should know that he is hypocrite.

Ṣifāt al-Shīʿa

Book 1, Chapter 48