The Sufficient (Vol 3) · Hadith 1486 (#Ḥadīth #2)
Chapter 57 | One Joining a Row, Alone in One Row or Away From the Prayer Leader More Than One Step
2ـ مُحَمَّدُ بْنُ إِسْمَاعِيلَ عَنِ الْفَضْلِ بْنِ شَاذَانَ عَنْ حَمَّادِ بْنِ عِيسَى عَنْ رِبْعِيٍّ عَنْ مُحَمَّدِ بْنِ مُسْلِمٍ قَالَ قُلْتُ لَهُ الرَّجُلُ يَتَأَخَّرُ وَهُوَ فِي الصَّلاَةِ قَالَ لاَ قُلْتُ فَيَتَقَدَّمُ قَالَ نَعَمْ مَا شَاءَ إِلَى الْقِبْلَةِ.
2. Muhammad ibn ’Isma‘il has narrated from al-Fadl ibn Shadhan from Hammad ibn ‘Isa from Rib‘i from Muhammad ibn Muslim who has said the following: “I once asked him (the Imam) , ‘Can a man move backward in Salah (prayer)?’ He (the Imam) said, ‘No, he cannot do so.’ I then asked, ‘Can he move forward?’ He (the Imam) said, ‘Yes, as much as he wants to al-Qiblah (al-Ka‘bah).’”
Gradings are classical jarḥ-wa-taʿdīl, name-matched to a rijāl index (not individually re-verified).