(He was not a liar) We used to pray behind the Prophet ﷺ and when he said, "Samiʿa l-lahu liman hamidah", none of us would bend his back (to go for prostration) till the Prophet ﷺ had placed his, forehead on the ground.  

كُنَّا نُصَلِّي خَلْفَ النَّبِيِّ ﷺ فَإِذَا قَالَ سَمِعَ اللَّهُ لِمَنْ حَمِدَهُ لَمْ يَحْنِ أَحَدٌ مِنَّا ظَهْرَهُ حَتَّى يَضَعَ النَّبِيُّ ﷺ جَبْهَتَهُ عَلَى الأَرْضِ