Abu Hurayra reported that the Prophet, may Allah bless him and grant him peace, said, "Allah created Adam, may Allah bless him and grant him peace, and his height was 60 spans. He said, 'Go and greet those (a group of angels who were sitting down) and listen to how they answer you. It is your greeting and the greeting of your descendants.' He said, 'Peace be upon you,' and they replied, 'Peace be upon you and the mercy of Allah.' They added, 'and the mercy of Allah'. All who enter the Garden will have his form, but creation has continued to decline until now.'"
Source: sunnah.com
Other translations
Arabic
حَدَّثَنَا عَبْدُ اللهِ بْنُ مُحَمَّدٍ، قَالَ: حَدَّثَنَا عَبْدُ الرَّزَّاقِ، قَالَ: أَخْبَرَنَا مَعْمَرٌ، عَنْ هَمَّامٍ، عَنْ أَبِي هُرَيْرَةَ، عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ: خَلَقَ اللَّهُ آدَمَ صلى الله عليه وسلم عَلَى صُورَتِهِ، وَطُولُهُ سِتُّونَ ذِرَاعًا، ثُمَّ قَالَ: اذْهَبْ، فَسَلِّمْ عَلَى أُولَئِكَ، نَفَرٌ مِنَ الْمَلاَئِكَةِ جُلُوسٌ، فَاسْتَمِعْ مَا يُحَيُّونَكَ بِهِ فَإِنَّهَا تَحِيَّتُكَ وَتَحِيَّةُ ذُرِّيَّتِكَ، فَقَالَ: السَّلاَمُ عَلَيْكُمْ، فَقَالُوا: السَّلاَمُ عَلَيْكَ وَرَحْمَةُ اللهِ، فَزَادُوهُ: وَرَحْمَةُ اللهِ، فَكُلُّ مَنْ يَدْخُلُ الْجَنَّةَ عَلَى صُورَتِهِ، فَلَمْ يَزَلْ يَنْقُصُ الْخَلْقُ حَتَّى الآنَ.
sunnah.com