But those that seek my soul, to destroy it, shall go into the lower parts of the earth. Professor Cheyne notes that "the psalmist has no sense of any incongruity between deeply spiritual musings and vehement denunciations of his enemies."
And this is certainly true. But it is to be remembered that he views his enemies, not merely as his own fees, but as the foes of God and of Israel. As the servant of God, he must hate those who are opposed to God; as the King of Israel, he must hate those who seek to injure and ruin his people.
He does not, however, desire for them suffering or torment; he only asks that they may be removed from this sphere into another world. (On David's conception of the lower world, see the comment upon Psalms 16:10 and Psalms 86:13.