The Book of Prayers
حَدَّثَنَا قُتَيْبَةُ بْنُ سَعِيدٍ، حَدَّثَنَا عَبْدُ الْعَزِيزِ، - يَعْنِي ابْنَ أَبِي حَازِمٍ - وَقَالَ قُتَيْبَةُ حَدَّثَنَا يَعْقُوبُ، - وَهُوَ ابْنُ عَبْدِ الرَّحْمَنِ الْقَارِيُّ - كِلاَهُمَا عَنْ أَبِي حَازِمٍ، عَنْ سَهْلِ بْنِ سَعْدٍ، بِمِثْلِ حَدِيثِ مَالِكٍ . وَفِي حَدِيثِهِمَا فَرَفَعَ أَبُو بَكْرٍ يَدَيْهِ فَحَمِدَ اللَّهَ وَرَجَعَ الْقَهْقَرَى وَرَاءَهُ حَتَّى قَامَ فِي الصَّفِّ .This hadith is transmitted by Sahl b. Sa'd in the same way as narrated by Malik, with the exception of these words:" Abu Bakr lifted his hands and praised Allah and retraced his (steps) till he stood in a row
From Sahih Muslim, whose reports the scholars accept as authentic.