Mishkat al-Masabih
Mishkat al-Masabih 959
Making Mention of God after the Prayer - Section 1
Arabic hadith text
عَنِ ابْنِ عَبَّاسٍ رَضِيَ اللَّهُ عَنْهُمَا قَالَ: كُنْتُ أَعْرِفُ انْقِضَاءَ صَلَاةِ رَسُولِ اللَّهِ صَلَّى الله عَلَيْهِ وَسلم بِالتَّكْبِيرِ
Translation
Ibn ‘Abbas said he used to know that God’s Messenger had finished his prayer when he heard the takbir. (Bukhari and Muslim.)