The Prophet ﷺ said, "Allah created Adam in His image, his height being sixty cubits. When He created him, He said, 'Go and greet that group of angels who are sitting, and listen to how they greet you, for it will be your greeting and the greeting of your descendants.'So he said, 'Peace be upon you.'They replied, 'Peace be upon you and the mercy of Allah,' adding 'and the mercy of Allah.'Everyone who enters Paradise will be in the form of Adam. Creation has continued to decrease in stature ever since, up to the present time."
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 يحيونك؛ فإنها تحيتك، وتحية ذريتك فقال: السلام عليكم فقالوا: السلام عليك ورحمة الله فزادوه ورحمة الله فكل من يدخل الجنة على صورة آدم، فلم يزل الخلق ينقص بعد حتى الآن.
Bukhari narrated it in "Seeking Permission" (6227), and Muslim in "The Description of Paradise" (2841), both of them from the narration of Abdul-Razzaq, from Mamar, from Hammam bin Munabbih, from Abu Hurairah, who mentioned it.