Surah Az-Zumar, ayah 13

قُلۡ إِنِّيٓ أَخَافُ إِنۡ عَصَيۡتُ رَبِّي عَذَابَ يَوۡمٍ عَظِيمٖ ١٣

Qul innī akhāfu in 'asaytu rabbī 'adhāba yawmin 'azīm

Say, "Indeed I fear, if I should disobey my Lord, the punishment of a tremendous Day."