Sayyiduna Abu Sa'id al-Khudri (may Allah be pleased with him) narrates: The Prophet (peace and blessings be upon him) was standing at Arafah and was supplicating like this: he raised both his hands and kept both hands level with his 'thanduwah' (this can mean the chest, the tip of the nose, or the front part of the body; perhaps the chest is meant here), and he kept his palms facing the ground.
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الأدعية / 17329