(and he was not a liar) When Messenger of Allah ﷺ said, "Samiʿa l-lahu liman hamidah" none of us bent his back (for prostration) till the Prophet ﷺ prostrated and then we would prostrate after him.
كَانَ رَسُولُ اللَّهِ ﷺ إِذَا قَالَ سَمِعَ اللَّهُ لِمَنْ حَمِدَهُ لَمْ يَحْنِ أَحَدٌ مِنَّا ظَهْرَهُ حَتَّى يَقَعَ النَّبِيُّ ﷺ سَاجِدًا ثُمَّ نَقَعُ سُجُودًا بَعْدَهُ
(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
When the Messenger of Allah ﷺ said: Allah listened to him who praised Him, none of us bent his back till he (the Holy Prophet) prostrated; we then, afterwards, went down in prostration.
كَانَ رَسُولُ اللَّهِ ﷺ إِذَا قَالَ سَمِعَ اللَّهُ لِمَنْ حَمِدَهُ لَمْ يَحْنِ أَحَدٌ مِنَّا ظَهْرَهُ حَتَّى يَقَعَ رَسُولُ اللَّهِ ﷺ سَاجِدًا ثُمَّ نَقَعُ سُجُودًا بَعْدَهُ
"كَانَ رَسُولُ الله ﷺ إِذَا قَالَ: سَمِعَ الله لِمَنْ حَمِدَهُ لَمْ يَحْنِ رَجُلٌ مِنَّا ظَهْرَهُ حَتَّى يَقَعَ النَّبِيُ ﷺ سَاجِدًا ثُمَّ نَقَعُ سُجُودًا".