His day] the day of his birth. It was thought that the days of the year had an existence of their own, so that any given day would come round again in its turn. Hence Job is not cursing a day which long ago ceased to be, but one which year by year comes back to blight the happiness of others as it blighted his: see on Job 3:5.
Related Commentaries of Job 3:1
Job 3:1
1 After this opened Job his mouth, and cursed his day.