قَالَ اَلصَّادِقُ عَلَيْهِ اَلسَّلاَمُ: "إِذَا شَهِدَ رَجُلٌ عَلَى شَهَادَةِ رَجُلٍ فَإِنَّ شَهَادَتَهُ تُقْبَلُ وَ هِيَ نِصْفُ شَهَادَةٍ وَ إِنْ شَهِدَ رَجُلاَنِ عَدْلاَنِ عَلَى شَهَادَةِ رَجُلٍ فَقَدْ ثَبَتَ شَهَادَةُ رَجُلٍ وَاحِدٍ".
Imam Jafar ibn Muhammad Al-Sadiq (a.s) said: "If a man testifies based on the testimony of another man, his testimony is accepted, and it counts as half a testimony. However, if two just men testify based on the testimony of one man, it is considered equivalent to the testimony of one man."