Al-Kāfi - Volume 3 > Mistake in Ruku‘
Hadith #2

2ـ عَلِيُّ بْنُ إِبْرَاهِيمَ عَنْ أَبِيهِ وَمُحَمَّدُ بْنُ إِسْمَاعِيلَ عَنِ الْفَضْلِ بْنِ شَاذَانَ جَمِيعاً عَنِ ابْنِ أَبِي عُمَيْرٍ عَنْ رِفَاعَةَ عَنْ أَبِي عَبْدِ الله (عَلَيْهِ الْسَّلام) قَالَ سَأَلْتُهُ عَنْ رَجُلٍ نَسِيَ أَنْ يَرْكَعَ حَتَّى يَسْجُدَ وَيَقُومَ قَالَ يَسْتَقْبِلُ.

2. Ali ibn Ibrahim has narrated from his father from and Muhammad ibn ’Isma‘il from al-Fadl ibn Shadhan all from ibn abu ‘Umayr from Rifa‘ah who has said the following: “I once asked abu ‘Abd Allah, ‘Alayhi al-Salam, about a man who forgets performing Ruku‘ (bowing down on one’s knees) until he performs Sajdah (prostration) and stands up. He (the Imam) said, ‘He performs Salah (prayer) again.’”