Sunan an-Nasa'i, Volume 2, Book 12, Hadith 1142 (DarusSalam) ⓘ

It was narrated from 'Abdullah bin Shaddad, this his father said: "The Messenger of Allah came out to us for one of the nighttime prayers, and he was carrying Hasan or Husain. The Messenger of Allah came forward and put him down, then he said the Takbir and started to pray. He prostrated during his prayer, and made the prostration lengthy." My father said: "I raised my head and saw the child on the back of the Messenger of Allah while he was prostrating so I went back to my prostration. When the Messenger of Allah finished praying, the people said: "O Messenger of Allah, you prostrated during the prayer for so long that we thought that something had happened or that you were receiving a revelation.' He said: 'No such thing happened. But my son was riding on my back and I did not like to disturb him until he had enough.'"

أَخْبَرَنَا عَبْدُ الرَّحْمَنِ بْنُ مُحَمَّدِ بْنِ سَلاَّمٍ، قَالَ حَدَّثَنَا يَزِيدُ بْنُ هَارُونَ، قَالَ أَنْبَأَنَا جَرِيرُ بْنُ حَازِمٍ، قَالَ حَدَّثَنَا مُحَمَّدُ بْنُ أَبِي يَعْقُوبَ الْبَصْرِيُّ، عَنْ عَبْدِ اللَّهِ بْنِ شَدَّادٍ، عَنْ أَبِيهِ، قَالَ خَرَجَ عَلَيْنَا رَسُولُ اللَّهِ صلى الله عليه وسلم فِي إِحْدَى صَلاَتَىِ الْعِشَاءِ وَهُوَ حَامِلٌ حَسَنًا أَوْ حُسَيْنًا فَتَقَدَّمَ رَسُولُ اللَّهِ صلى الله عليه وسلم فَوَضَعَهُ ثُمَّ كَبَّرَ لِلصَّلاَةِ فَصَلَّى فَسَجَدَ بَيْنَ ظَهْرَانَىْ صَلاَتِهِ سَجْدَةً أَطَالَهَا ‏.‏ قَالَ أَبِي فَرَفَعْتُ رَأْسِي وَإِذَا الصَّبِيُّ عَلَى ظَهْرِ رَسُولِ اللَّهِ صلى الله عليه وسلم وَهُوَ سَاجِدٌ فَرَجَعْتُ إِلَى سُجُودِي فَلَمَّا قَضَى رَسُولُ اللَّهِ صلى الله عليه وسلم الصَّلاَةَ قَالَ النَّاسُ يَا رَسُولَ اللَّهِ إِنَّكَ سَجَدْتَ بَيْنَ ظَهْرَانَىْ صَلاَتِكَ سَجْدَةً أَطَلْتَهَا حَتَّى ظَنَنَّا أَنَّهُ قَدْ حَدَثَ أَمْرٌ أَوْ أَنَّهُ يُوحَى إِلَيْكَ ‏.‏ قَالَ ‏ "‏ كُلُّ ذَلِكَ لَمْ يَكُنْ وَلَكِنَّ ابْنِي ارْتَحَلَنِي فَكَرِهْتُ أَنْ أُعَجِّلَهُ حَتَّى يَقْضِيَ حَاجَتَهُ ‏" ‏ ‏.‏