5ـ عَلِيُّ بْنُ إِبْرَاهِيمَ عَنْ أَبِيهِ عَنِ ابْنِ أَبِي عُمَيْرٍ عَنْ حَمَّادِ بْنِ عُثْمَانَ عَنِ الْحَلَبِيِّ عَنْ أَبِي عَبْدِ الله (عَلَيْهِ الْسَّلام) قَالَ إِذَا أَدْرَكْتَ الإِمَامَ قَدْ رَكَعَ فَكَبَّرْتَ وَرَكَعْتَ قَبْلَ أَنْ يَرْفَعَ رَأْسَهُ فَقَدْ أَدْرَكْتَ الرَّكْعَةَ فَإِنْ رَفَعَ الإِمَامُ رَأْسَهُ قَبْلَ أَنْ تَرْكَعَ فَقَدْ فَاتَتْكَ الرَّكْعَةُ.
5. Ali ibn Ibrahim has narrated from his father from Ibn Abi ‘Umayr from Hammad ibn ‘Uthaman from al-Halabiy who has said the following: “Abu ‘Abd Allah (a.s.), has said, ‘If you join the Imam for one Rak‘at, say Takbir (Allah is great beyond description). You must perform Ruku‘ (bowing down on one’s knees) before he raises his head (from Ruku‘). You have joined for one Rak‘at but if he raises his head before you are in Ruku‘, you have missed one Rak‘at.’”