Silsilah as-Sahihah 536 — Following the Imam

It is narrated from Sayyiduna Abu Musa (may Allah be pleased with him), he says: The Messenger of Allah (peace and blessings of Allah be upon him) said: "My body has become heavy, so you should bow (ruku) when I bow, and prostrate (sajdah) when I prostrate, and let it never happen that anyone precedes me in bowing or prostration."