It is narrated from Hazrat Abu Saeed Khudri (may Allah be pleased with him) that the Prophet (peace and blessings of Allah be upon him) was standing in the plain of Arafat making supplication in such a way that he had raised his hands in front of his chest and the backs of his palms were facing towards the ground.
Hadith Referenceمسند احمد / مسند المكثرين من الصحابة / 11911
Hadith Gradingحکم دارالسلام:إسناده ضعيف لضعف بشر بن حرب الأزدي