Ibn Abbas said : To raise the voice for making the mention of Allah after the people had finished their obligatory prayer was for in vogue the time of the Messenger of Allah (May peace be upon him). Ibn ‘Abbas said : I used to know by it when they finished the prayer and would listen to it (making the mention of Allah).
Source: sunnah.com
Other translations
Arabic
حَدَّثَنَا يَحْيَى بْنُ مُوسَى الْبَلْخِيُّ، حَدَّثَنَا عَبْدُ الرَّزَّاقِ، أَخْبَرَنِي ابْنُ جُرَيْجٍ، أَخْبَرَنَا عَمْرُو بْنُ دِينَارٍ، أَنَّ أَبَا مَعْبَدٍ، مَوْلَى ابْنِ عَبَّاسٍ أَخْبَرَهُ أَنَّ ابْنَ عَبَّاسٍ أَخْبَرَهُ أَنَّ رَفْعَ الصَّوْتِ لِلذِّكْرِ حِينَ يَنْصَرِفُ النَّاسُ مِنَ الْمَكْتُوبَةِ كَانَ ذَلِكَ عَلَى عَهْدِ رَسُولِ اللَّهِ صلى الله عليه وسلم وَأَنَّ ابْنَ عَبَّاسٍ قَالَ كُنْتُ أَعْلَمُ إِذَا انْصَرَفُوا بِذَلِكَ وَأَسْمَعُهُ .
sunnah.com