Remove grace, and you have nothing whereby to be saved. Remove free will and you have nothing that could be saved.
For I do not seek to understand in order to believe, but I believe in order to understand. For I believe this: unless I believe, I will not understand.
Thus you are just not because you give what is owed, but because you do what is appropriate to you as the highest good.
Spare me through your mercy, do not punish me through your justice.