ENOfficial
It was narrated from ‘Abbas bin ‘Abdul-Muttalib that he heard the Prophet (ﷺ) say: “When a person prostrates, seven parts of his body prostrate with him: His face, his two hands, his two knees, and his two feet.”
Source: sunnah.com
Other translations
Arabic
حَدَّثَنَا يَعْقُوبُ بْنُ حُمَيْدِ بْنِ كَاسِبٍ، حَدَّثَنَا عَبْدُ الْعَزِيزِ بْنُ أَبِي حَازِمٍ، عَنْ يَزِيدَ بْنِ الْهَادِ، عَنْ مُحَمَّدِ بْنِ إِبْرَاهِيمَ التَّيْمِيِّ، عَنْ عَامِرِ بْنِ سَعْدٍ، عَنِ الْعَبَّاسِ بْنِ عَبْدِ الْمُطَّلِبِ، أَنَّهُ سَمِعَ النَّبِيَّ ـ صلى الله عليه وسلم ـ يَقُولُ " إِذَا سَجَدَ الْعَبْدُ سَجَدَ مَعَهُ سَبْعَةُ آرَابٍ: وَجْهُهُ وَكَفَّاهُ وَرُكْبَتَاهُ وَقَدَمَاهُ " .
sunnah.com