Sunan an-Nasa'i 1022
It was narrated from Ya'la bin Mamlak that :
He asked Umm Salamah about the recitation and prayer of the Messenger of Allah (ﷺ) and she said: "Why do you want to know about his prayer?" Then she described his recitation and as being so measured and clear that each letter could be distinguished.
أَخْبَرَنَا قُتَيْبَةُ، قَالَ حَدَّثَنَا اللَّيْثُ بْنُ سَعْدٍ، عَنْ عَبْدِ اللَّهِ بْنِ عُبَيْدِ اللَّهِ بْنِ أَبِي مُلَيْكَةَ، عَنْ يَعْلَى بْنِ مَمْلَكٍ، أَنَّهُ سَأَلَ أُمَّ سَلَمَةَ عَنْ قِرَاءَةِ، رَسُولِ اللَّهِ صلى الله عليه وسلم وَصَلاَتِهِ قَالَتْ مَا لَكُمْ وَصَلاَتَهُ ثُمَّ نَعَتَتْ فَإِذَا هِيَ تَنْعَتُ قِرَاءَتَهُ مُفَسَّرَةً حَرْفًا حَرْفًا ‏.‏