The Messenger of Allah ﷺ said, "The people of Paradise will enter Paradise in the form of Adam, sixty cubits in height, and it was on that measure that their navel cords were cut."
أن رسول الله ﷺ قال: إن أهل الجنة يدخلون الجنة على قدر آدم ستون ذراعا، وعلى ذلك قطعت سررهم.
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Tabarani narrated it in Musnad Shamiyin (2074), and Abu Naeem in Sifat al-Jannah (248), both through the route of Harmala bin Yahya, who said, Ibn Wahb narrated to us, saying, Muawiya bin Salih narrated to me, from Abdul-Wahhab bin Bukht, from Abu Zinad, from Araj, from Abu Hurairah, and he related it.Its chain of transmission is hasan because of Abdul-Wahhab bin Bukht, for there is disagreement about him, though his hadith is hasan. As for his statement, "and it was upon that their umbilical cords were cut," I have not found it with anyone other than him.