٤- مُحَمَّدُ بْنُ يَحْيَى عَنْ أَحْمَدَ بْنِ مُحَمَّدٍ عَنِ ابْنِ مَحْبُوبٍ عَنْ هِشَامِ بْنِ سَالِمٍ عَنْ عَمَّارِ بْنِ مَرْوَانَ قَالَ سَأَلْتُ أَبَا عَبْدِ اللهِ (عَلَيْهِ السَّلام) أَوْ قَالَ سَأَلَهُ بَعْضُ أَصْحَابِنَا عَنِ الرَّجُلِ يَشْهَدُ لأبِيهِ أَوِ الأبِ يَشْهَدُ لابْنِهِ أَوِ الأخِ لأخِيهِ قَالَ لا بَأْسَ بِذَلِكَ إِذَا كَانَ خَيِّراً جَازَتْ شَهَادَتُهُ لأبِيهِ وَالأبِ لابْنِهِ وَالأخِ لأخِيهِ. 
4. Muhammad ibn Yahya has narrated from Ahmad ibn Muhammad from ibn Mahbub from Hisham ibn Salim from ‘Ammar ibn Marwan who has narrated the following: “I or a certain persons of our people asked abu ‘Abd Allah , about the case of a man who testifies for his father or a father testifies for his son or for his brother. He (the Imam) said, ‘It is not harmful if it is for a good cause. His testimony is permissible for his father as is the case with a father’s testimony for his son or a brother’s testimony for his brother.’” 