From Sahih Muslim (Hadith 1064):
Al-Bara' reported:They (the Companions) said prayer with the Messenger of Allah (ﷺ), and they bowed when he (the Holy Prophet) bowed. and when he raised his head after bowing, he pronounced:" Allah listened to him who praised Him," and we kept standing till we saw him placing his face on the ground and then we followed him
Reference: Muslim 1064