Musnad Ahmad

It is narrated from Hazrat Abu Hurairah (may Allah be pleased with him) that when the Noble Prophet (peace and blessings be upon him) would stand for prayer and go into bowing (ruku‘), he would say the takbeer, and when he would raise his back from ruku‘, he would say "Sami‘ Allahu liman hamidah," and while standing he would say "Rabbana lakal hamd." Then, when going into prostration (sajdah), when raising his head from prostration, when going into prostration again, and when raising his head, he would say the takbeer. He would do this throughout the entire prayer until he completed the prayer. Similarly, after the sitting (qa‘dah), when he would stand up after two rak‘ahs, he would also say the takbeer.