The Sufficient (Vol 3) · Hadith 1207 (#Ḥadīth #4)
Chapter 24 | Ruku‘ (Kneeling) and Readings therein and When Standing up Straight Thereafter
4ـ مُحَمَّدُ بْنُ يَحْيَى عَنْ أَحْمَدَ بْنِ مُحَمَّدٍ عَنِ الْحُسَيْنِ بْنِ سَعِيدٍ عَنْ فَضَالَةَ بْنِ أَيُّوبَ عَنْ أَبِي الْمَغْرَاءِ عَنْ أَبِي بَصِيرٍ عَنْ أَبِي عَبْدِ الله (عَلَيْهِ الْسَّلام) قَالَ قَالَ أَمِيرُ الْمُؤْمِنِينَ (صلّى اللهُ عَلَيْهِ وَآلِه) مَنْ لَمْ يُقِمْ صُلْبَهُ فِي الصَّلاَةِ فَلاَ صَلاَةَ لَهُ.
4. Muhammad ibn Yahya has narrated from Ahmad ibn Muhammad from al-Husayn ibn Sa‘id from Fadalah ibn Ayyub from abu al- Mighra’ from abu Basir who has said the following: “Abu ‘Abd Allah , has said that ’Amir al-Mu’minin has said, ‘One who does not straighten his back during Salah (prayer), his Salah (prayer) is not valid.’”
Gradings are classical jarḥ-wa-taʿdīl, name-matched to a rijāl index (not individually re-verified).