بُلُوغُ الْمَرَامِ
Bulugh al-Maram 348
The Book of Prayer
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]
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].
Sunnah.com reference: Book 2, Hadith 249