The Prophet ﷺ said, "Allah created Adam in His image, sixty cubits tall. When He created him, He said, 'Go and greet those angels seated over there, and listen to how they greet you, for it will be the greeting of your descendants.'So Adam said, 'Peace be upon you.'They replied, 'Peace be upon you and the mercy of Allah,' adding the words 'and the mercy of Allah.'Everyone who enters Paradise will be in the form of Adam, and creation has continued to diminish in size ever since."
عن النبي ﷺ قال: خلق الله آدم على صورته، طوله ستون ذراعا. فلما خلقه قال: اذهب فسلم على أولئك النفر من الملائكة جلوس، فاستمع ما يحبونك فإنها تحية ذريتك. فقال: السلام عليكم. فقالوا: السلام عليك ورحمة الله، فزادوا: ورحمة الله، فكل من يدخل الجنة على صورة آدم، فلم يزل الخلق ينقص بعد الآن.
Bukhari related it in the Book of Seeking Permission (6227), and Muslim in the Book of Paradise and the Description of Its Bliss and Its People (2841), both from the hadith of Abdul-Razzaq, who said, Mamar informed us, from Hammam bin Munabbih, from Abu Hurairah, and he related the hadith.