6 But this man being troubled and made sad was praying, his eye being disturbed as it were on account of anger. But the anger of a brother if it shall have been inveterate is then hatred. Anger does trouble the eye, hatred does quench it: anger is a straw, hatred is a beam. Sometimes you hate and chidest an angry man: in you is hatred, in him whom you chide anger: with reason to you is said, “Cast out first the beam from your own eye, and so you shall see to cast out the straw from your brother's eye.” For that you may know how much difference there is between anger and hatred: day by day men are angry with their sons, show me them that hate their sons!
This man being troubled was praying even when made sad, wrestling against all revilings of all revilers; not in order that he might conquer any one of them by giving back reviling, but that he might not hate any one of them. Hence he prays, hence asks: “From the voice of the enemy and from the tribulation of the sinner.” “My heart has been troubled in me”. This is the same as elsewhere has been said, “My eye because of anger has been troubled.” And if eye has been troubled, what follows?
“And fear of death has fallen upon me.” Our life is love: if life is love, death is hatred. When a man has begun to fear lest he should hate him that he was loving, it is death he is fearing; and a sharper death, and a more inward death, whereby soul is killed, not body. You minded a man raging against you; what was he to do, against whom your own Lord had given you security, saying, “Fear not them that kill the body”? He by raging kills body, thou by keeping hatred hast killed soul; and he the body of another, thou your own soul. “Fear,” therefore, “of death has fallen upon me.”
Source: The Enarrations, or Expositions, on the Psalms (New Advent)