Sayyiduna Abu Huraira (may Allah be pleased with him) said that whoever raises or lowers his head before the Imam, his forehead is in the hand of Satan.

Imam Malik, may Allah have mercy on him, said that if a person forgetfully raises his head before the imam in bowing (ruku) or prostration (sajdah), then the Sunnah is that he should return to the bowing or prostration and not wait for the imam to raise his head. And whoever does this intentionally has made a mistake, because the Messenger of Allah, peace and blessings be upon him, said: "The imam is appointed only to be followed, so do not differ with him." That is, do not perform the acts before or after him. And our master Abu Huraira, may Allah be pleased with him, said that whoever raises or lowers his head before the imam, his forehead is in the hand of Satan.