كتاب الْمَسَاجِدِ وَمَوَاضِعِ الصَّلاَةِ
5  
The Book of Mosques and Places of Prayer
(5)
Chapter: The recommendation to place the hands on the knees when bowing, and the abrogation of tatbiq
(5)
باب النَّدْبِ إِلَى وَضْعِ الأَيْدِي عَلَى الرُّكَبِ فِي الرُّكُوعِ وَنَسْخِ التَّطْبِيقِ ‏
Sahih Muslim 535 a

Mus'ab b. Sa'd reported:

I said prayer by the side of my father and placed my hands between my knees. My father said to me: Place your hands on your knees. I repeated that (the previous act) for the second time, and he struck at my hands and said: We have been forbidden to do so and have been commanded to place our palms on the knees.
حَدَّثَنَا قُتَيْبَةُ بْنُ سَعِيدٍ، وَأَبُو كَامِلٍ الْجَحْدَرِيُّ - وَاللَّفْظُ لِقُتَيْبَةَ - قَالاَ حَدَّثَنَا أَبُو عَوَانَةَ، عَنْ أَبِي يَعْفُورٍ، عَنْ مُصْعَبِ بْنِ سَعْدٍ، قَالَ صَلَّيْتُ إِلَى جَنْبِ أَبِي قَالَ وَجَعَلْتُ يَدَىَّ بَيْنَ رُكْبَتَىَّ فَقَالَ لِي أَبِي اضْرِبْ بِكَفَّيْكَ عَلَى رُكْبَتَيْكَ ‏.‏ قَالَ ثُمَّ فَعَلْتُ ذَلِكَ مَرَّةً أُخْرَى فَضَرَبَ يَدَىَّ وَقَالَ إِنَّا نُهِينَا عَنْ هَذَا وَأُمِرْنَا أَنْ نَضْرِبَ بِالأَكُفِّ عَلَى الرُّكَبِ ‏.‏
Reference : Sahih Muslim 535a
In-book reference : Book 5, Hadith 34
USC-MSA web (English) reference : Book 4, Hadith 1089
  (deprecated numbering scheme)