Musnad Ahmad

It is narrated from Hazrat Aisha (may Allah be pleased with her) that the Prophet (peace and blessings be upon him) would begin the prayer with Takbeer and would start the recitation with Surah Al-Fatiha. When he would go into Ruku, he would neither raise his head high nor lower it, but would keep it in between. When he would rise from Ruku, he would not perform the second prostration until he sat up straight. In every two rak'ahs, he would recite "At-Tahiyyat". He forbade keeping the heels upright like Satan and would spread his left foot and keep his right foot upright. He also forbade any of us from spreading our arms like a dog, and he would end the prayer with Salam.