وَ رَوَى عَمْرُو بْنُ جُمَيْعٍ عَنْ أَبِي عَبْدِ اَللَّهِ عَنْ أَبِيهِ عَلَيْهِمَا اَلسَّلاَمُ قَالَ: "أَشْهِدْ عَلَى شَهَادَتِكَ مَنْ يَنْصَحُكَ" قَالُوا أَصْلَحَكَ اَللَّهُ كَيْفَ يَزِيدُ وَ يَنْقُصُ قَالَ "لاَ وَ لَكِنْ مَنْ يَحْفَظُهَا عَلَيْكَ". وَ لَا تَجُوزُ شَهَادَةٌ عَلَى شَهَادَةٍ عَلَى شَهَادَةٍ.
Amr ibn Jumay' narrated from Abu Abdullah Imam Jafar ibn Muhammad Al-Sadiq (a.s) from his father, Imam Muhammad ibn Ali Al-Baqir (a.s): Imam (a.s) said: "Let someone trustworthy bear witness to your testimony." They asked: 'May Allah (swt) keep you well, how can it increase or decrease?' Imam (a.s) replied: "No, but it should be someone who preserves it for you." Imam (a.s) also said: "It is not permissible to testify upon a testimony that is based on another testimony."