Man Lā Yaḥḍuruh al-Faqīh

Hadith 476
funeral-prayer
477 - وَ سَأَلَ اَلْيَسَعُ بْنُ عَبْدِ اَللَّهِ اَلْقُمِّيُّ أَبَا عَبْدِ اَللَّهِ عَلَيْهِ اَلسَّلاَمُ: عَنِ اَلرَّجُلِ يُصَلِّي عَلَى اَلْجِنَازَةِ وَحْدَهُ قَالَ «نَعَمْ» قُلْتُ فَاثْنَانِ يُصَلِّيَانِ عَلَيْهَا قَالَ «نَعَمْ وَ لَكِنْ يَقُومُ اَلْآخَرُ خَلْفَ اَلْآخَرِ وَ لاَ يَقُومُ بِجَنْبِهِ.
Hadith.477 - Al-Yasa' ibn Abdullah al-Qummi asked Imam Jafar ibn Muhammad Al-Sadiq (as) about a man praying over a funeral alone. Imam (as) replied: "Yes, he may do so." I then asked: "What if there are two people praying?" The Imam said: "Yes, but one should stand behind the other, not next to him."
Source: Shaykh Muḥammad b. ʿAlī al-Ṣaduq