حَدَّثَنَا عُقْبَةُ بْنُ مُكْرَمٍ، حَدَّثَنَا سَلْمُ بْنُ قُتَيْبَةَ، عَنْ عُمَرَ بْنِ نَبْهَانَ، عَنْ قَتَادَةَ، عَنْ أَنَسِ بْنِ مَالِكٍ، قَالَ رَأَيْتُ رَسُولَ اللَّهِ صلى الله عليه وسلم يَدْعُو هَكَذَا بِبَاطِنِ كَفَّيْهِ وَظَاهِرِهِمَا .
Narrated Anas ibn Malik:
I saw the Messenger of Allah (ﷺ) supplicating Allah in this manner with the palms of his hands and also with their backs upwards.
Reference: Sunan Abi Dawud 1487
In-book : Book 8, Hadith 72
English translation : Book 8, Hadith 1482