All the more are human works mortal sins when they are done without fear and in unadulterated, evil self-security.

The inevitable deduction from the preceding thesis is clear. For where there is no fear there is no humility. Where there is no humility there is pride, and where there is pride there are the wrath and judgment of God, for God opposes the haughty. Indeed, if pride would cease there would be no sin anywhere. 

The Annotated Luther, vol. 1, The Roots of Reform, Heidleberg Disputation 1518, no. 8
https://ref.ly/o/annotlutv1/462431?length=418