The Sufficient (Vol 3) · Hadith 1476 (#Ḥadīth #6)
Chapter 56 | One Performing Salah (Prayer) Partially behind an Imam Who then Asks Him to Lead because of Losing his Wudu’
6ـ مُحَمَّدُ بْنُ يَحْيَى عَنْ أَحْمَدَ بْنِ مُحَمَّدٍ عَنْ عَلِيِّ بْنِ النُّعْمَانِ عَنِ ابْنِ مُسْكَانَ عَنْ سُلَيْمَانَ بْنِ خَالِدٍ قَالَ قَالَ أَبُو عَبْدِ الله (عَلَيْهِ الْسَّلام) فِي الرَّجُلِ إِذَا أَدْرَكَ الإِمَامَ وَهُوَ رَاكِعٌ فَكَبَّرَ وَهُوَ مُقِيمٌ صُلْبَهُ ثُمَّ رَكَعَ قَبْلَ أَنْ يَرْفَعَ الإِمَامُ رَأْسَهُ فَقَدْ أَدْرَكَ.
6. Muhammad ibn Yahya has narrated from Ahmad ibn Muhammad from Ali ibn al-Nu‘man from ibn Muskan from Sulayman ibn Khalid who has said the following: “Abu ‘Abd Allah , has said, ‘If a man finds the Imam in Ruku‘ (bowing down on one’s knees), says Takbir (Allah is great beyond description) while his back is straight and performs Ruku‘ before the Imam raises his head, has joined for one Rak‘at.’”
Gradings are classical jarḥ-wa-taʿdīl, name-matched to a rijāl index (not individually re-verified).