Sunan Abi Dawud 1490
In another version Ibn 'Abbas said:
Earnest supplication should be made like this: he raised his hand and made his palms in the direction of his face.
حَدَّثَنَا عَمْرُو بْنُ عُثْمَانَ، حَدَّثَنَا سُفْيَانُ، حَدَّثَنِي عَبَّاسُ بْنُ عَبْدِ اللَّهِ بْنِ مَعْبَدِ بْنِ عَبَّاسٍ، بِهَذَا الْحَدِيثِ قَالَ فِيهِ وَالاِبْتِهَالُ هَكَذَا وَرَفَعَ يَدَيْهِ وَجَعَلَ ظُهُورَهُمَا مِمَّا يَلِي وَجْهَهُ ‏.‏