Musnad Ahmad 30:3253

Muhammad ibn Ja‘far narrated to us, he said: ‘Awf narrated to us, from Khallas, from Abu Hurayrah, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "While a young man was walking in a garment, strutting in it, letting his lower garment hang low, the earth swallowed him up. He will continue to sink into it until the Day of Resurrection."