إِذَا شَهِدَ رَجُلٌ عَلَى شَهَادَةِ رَجُلٍ فَإِنَّ شَهَادَتَهُ تُقْبَلُ وَ هِيَ نِصْفُ شَهَادَةٍ[3] وَ إِنْ شَهِدَ رَجُلَانِ عَدْلَانِ عَلَى شَهَادَةِ رَجُلٍ فَقَدْ ثَبَتَ شَهَادَةُ رَجُلٍ وَاحِدٍ
Hadith.3351 - Imam Jafar ibn Muhammad Al-Sadiq (as) 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."