Sahih Ibn Khuzaymah

Imam Abu Bakr, may Allah have mercy on him, says that in the narration of Sayyiduna Abu Musa, may Allah be pleased with him, it is stated: "Indeed, the Imam prostrates before you and raises his head before you, so this will become equal for him." (That is, your prostrating late and raising your head late will make your prostration and that of the Imam equal.) And in the narration of Sayyiduna Muawiyah, may Allah be pleased with him, it is stated: "However much I go into prostration before you, you will attain that amount after I raise my head."