By Wrath Sin we mean wrath out of control, which can become hatred. Wrath, also called anger, is a consequence of arrogance.
Arrogance does not accept contradiction, that's why we conceive anger. Anger hinders our mental peace, which is totally necessary in order to grow spiritually.
This vice hinders us also to make progress in Love and Justice.
“But love your enemies, and do good, and lend, expecting nothing in return; and your reward will be great, and you will be sons of the Most High; for He Himself is kind to ungrateful and evil men.” - Luke 6:35
My sisters and brothers in Christ, we have to forgive in order to be free of the capital sin of Wrath. This bad habit separates us from friends and family. It makes us step over other people's rights and feelings.
First of all: Prayer! Ask God to help you love that one person who is the most difficult for you to love
He can cure you in one instant. But if He lets you wait for some time, maybe He wants to teach you something! Always keep in mind that God disapproves of revenge.
We have to admit that we need the Grace of God to have self control.
Silence, exterior and interior, will sooth Wrath and dominate it.
Remember: Hatred is the bad fruit of an uncontrolled anger!