Imam Ahmad : 22780

حَدَّثَنَا مَرْوَانُ بْنُ شُجَاعٍ حَدَّثَنِي خُصَيْفٌ عَنْ مُجَاهِدٍ عَنِ ابْنِ عُمَرَ أَنَّهُ سَأَلَ بِلَالًا فَأَخْبَرَهُ أَنَّ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ رَكَعَ رَكْعَتَيْنِ جَعَلَ الْأُسْطُوَانَةَ عَنْ يَمِينِهِ وَتَقَدَّمَ قَلِيلًا وَجَعَلَ الْمَقَامَ خَلْفَ ظَهْرِهِ

Narrated to us [Marwan bin Syuja'] had told me [Khushaif] from [Mujahid] from [Ibn 'Umar] he asked [Bilal] then Bilal told him that the Messenger of Allah Peace be upon him wa sallam prayed two rak'ahs, he placed the pillar on the right, moved forward a little and placed the station behind him.