Musnad Ahmad 27:1439

Musa ibn Dawud narrated to us, Ibn Lahi'ah narrated to us, from Khalid ibn Abi 'Imran, from Nafi', from Ibn 'Umar, that the Prophet, peace and blessings of Allah be upon him, said: "Whoever performs the morning prayer, he is under the protection (dhimmah) of Allah. So do not violate the protection of Allah, for whoever violates His protection, Allah will pursue him until He throws him upon his face [into the Fire]."