curse God - rather, “renounce” God. (See on Job 1:5) [Umbreit]. However, it was usual among the heathens, when disappointed in their prayers accompanied with offerings to their gods, to reproach and curse them.
and die - that is, take thy farewell of God and so die. For no good is to be got out of religion, either here or hereafter; or, at least, not in this life [Gill]; Nothing makes the ungodly so angry as to see the godly under trial not angry.