مُوَطَّأُ مَالِكٍ
Muwatta Malik 388
Shortening the Prayer
وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ نُعَيْمِ بْنِ عَبْدِ اللَّهِ الْمُجْمِرِ، أَنَّهُ سَمِعَ أَبَا هُرَيْرَةَ، يَقُولُ إِذَا صَلَّى أَحَدُكُمْ ثُمَّ جَلَسَ فِي مُصَلاَّهُ لَمْ تَزَلِ الْمَلاَئِكَةُ تُصَلِّي عَلَيْهِ اللَّهُمَّ اغْفِرْ لَهُ اللَّهُمَّ ارْحَمْهُ فَإِنْ قَامَ مِنْ مُصَلاَّهُ فَجَلَسَ فِي الْمَسْجِدِ يَنْتَظِرُ الصَّلاَةَ لَمْ يَزَلْ فِي صَلاَةٍ حَتَّى يُصَلِّيَ .
Yahya related to me from Malik from Nuaym ibn Abdullah al-Mujmir that he heard Abu Hurayra say, "If any one of you prays and then sits down in the spot where he has prayed, the angels ask blessings on him saying, 'Allah, forgive him. Allah, have mercy on him.' And if he moves from the spot where he has prayed and sits elsewhere in the mosque waiting for the prayer, he remains in prayer until he prays."
Arabic/English book reference: Book 9, Hadith 57