Musnad Ahmad 130:1

Yahya ibn Ishaq narrated to us, he said: Ibn Lahi'ah informed us, from Yazid ibn Abi Habib, he said: Aslam Abu 'Imran informed me, from Hubayb al-Ghifari, he said: The Messenger of Allah, peace and blessings of Allah be upon him, said: "Whoever treads upon his lower garment out of pride, he treads in the Fire of Hell."