Abu Hurairah reported,

The Messenger of Allah ﷺ taught us not to get ahead of the imam in ruku or sujud. When he says the takbir, say it after him. When he goes into sujud, follow him. When he recites "not of those who have earned Your anger, nor of those who have gone astray" [Fatihah 1:7], say "Ameen," for if it coincides with the speech of the angels, everyone in the masjid is forgiven. And when he says, "Allah hears the one who praises Him," say, "Our Lord, to You belongs all praise."

وبإسناده قال كان رسول الله ﷺ يعلمنا أن لا نبادر الإمام بالركوع والسجود وإذا كبر فكبروا وإذا سجد فاسجدوا وإذا قال {غير المغضوب عليهم ولا الضالين} فقولوا آمين فإذا وافق كلام الملائكة غفر لمن في المسجد وإذا قال سمع الله لمن حمده فقولوا ربنا لك الحمد