Musnad Ahmad 261
It was narrated from Ubaid bin Adam, Abu Maryam and Abu Shu`aib that:
`Umar bin al-Khattab was in al-Jabiyah and he mentioned the conquest of Baitul-Maqdis (Jerusalem). Then Abu Salamah said: Abu Sinan told me, from `Ubaid bin Adam that he said: I heard `Umar bin al-Khattab say to Ka`b: Where do you think I should pray? He said: It you listen to me, you will pray behind the rock and all of al-Quds (Jerusalem) will be in front of you. `Umar said: You are suggesting something similar to the Jewish way; rather I shall pray where the Messenger of Allah (ﷺ) prayed. He went forward to the qiblah and prayed, then he came and spread his upper garment and swept the place, collecting garbage in his upper garment, and the people swept it too.
حَدَّثَنَا أَسْوَدُ بْنُ عَامِرٍ، حَدَّثَنَا حَمَّادُ بْنُ سَلَمَةَ، عَنْ أَبِي سِنَانٍ، عَنْ عُبَيْدِ بْنِ آدَمَ، وَأَبِي، مَرْيَمَ وَأَبِي شُعَيْبٍ أَنَّ عُمَرَ بْنَ الْخَطَّابِ، رَضِيَ اللَّهُ عَنْهُ كَانَ بِالْجَابِيَةِ فَذَكَرَ فَتْحَ بَيْتِ الْمَقْدِسِ قَالَ فَقَالَ أَبُو سَلَمَةَ فَحَدَّثَنِي أَبُو سِنَانٍ عَنْ عُبَيْدِ بْنِ آدَمَ قَالَ سَمِعْتُ عُمَرَ بْنَ الْخَطَّابِ رَضِيَ اللَّهُ عَنْهُ يَقُولُ لِكَعْبٍ أَيْنَ تُرَى أَنْ أُصَلِّيَ فَقَالَ إِنْ أَخَذْتَ عَنِّي صَلَّيْتَ خَلْفَ الصَّخْرَةِ فَكَانَتْ الْقُدْسُ كُلُّهَا بَيْنَ يَدَيْكَ فَقَالَ عُمَرُ رَضِيَ اللَّهُ عَنْهُ ضَاهَيْتَ الْيَهُودِيَّةَ لَا وَلَكِنْ أُصَلِّي حَيْثُ صَلَّى رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ فَتَقَدَّمَ إِلَى الْقِبْلَةِ فَصَلَّى ثُمَّ جَاءَ فَبَسَطَ رِدَاءَهُ فَكَنَسَ الْكُنَاسَةَ فِي رِدَائِهِ وَكَنَسَ النَّاسُ‏.‏