كتاب الصلاة
2  
The Book of Prayer
Bulugh al-Maram 348
Narrated Abu Bakra (RA):
Whenever the Prophet (ﷺ) received a matter which pleased him he used to prostrate to Allah [out of thankfulness]. [Reported by al-Khamsa except an-Nasa'i].
وَعَنْ أَبِي بَكْرَةَ ‏- رضى الله عنه ‏- أَنَّ اَلنَّبِيَّ ‏- صلى الله عليه وسلم ‏-{ كَانَ إِذَا جَاءَهُ أَمْرٌ يَسُرُّهُ خَرَّ سَاجِداً لِلَّهِ } رَوَاهُ اَلْخَمْسَةُ إِلَّا النَّسَائِيَّ .‏ 1
Reference : Bulugh al-Maram 348
In-book reference : Book 2, Hadith 348
English translation : Book 2, Hadith 343
Hadith Text
Reference