The Sufficient (Vol 3) · Hadith 1446 (#Ḥadīth #3)
Chapter 51 | Who Is an Undesirable Leader in Salah (prayer)? Can a Slave Lead Salah (prayer)? Who Is Most Rightful to Lead Salah (prayer)
3ـ وَبِهَذَا الإِسْنَادِ فِي رَجُلَيْنِ اخْتَلَفَا فَقَالَ أَحَدُهُمَا كُنْتُ إِمَامَكَ وَقَالَ الآخَرُ أَنَا كُنْتُ إِمَامَكَ فَقَالَ صَلاَتُهُمَا تَامَّةٌ قُلْتُ فَإِنْ قَالَ كُلُّ وَاحِدٍ مِنْهُمَا كُنْتُ أَئْتَمُّ بِكَ قَالَ صَلاَتُهُمَا فَاسِدَةٌ وَلْيَسْتَأْنِفَا.
3. Through the chain of narrators as that of the previous Hadith is the following narration: “If two people disagree and one says, ‘I was your Imam’ and the other says, ‘I was your Imam’ he (the Imam) said, ‘Both persons’ Salah (prayer) is complete.’ I (the narrator) then asked, ‘What happens if each one says, ‘I followed you.’ He (the Imam) said, ‘Both persons’ Salah (prayer) is invalid. They must perform it again.’”
Gradings are classical jarḥ-wa-taʿdīl, name-matched to a rijāl index (not individually re-verified).