As Purim approaches, we see the power of hatred. Haman hated the Jews to such an extent that it consumed him. His ultimate downfall came because of the very high gallows he made for Mordechai.
Hatred is generally a very damaging emotion on any level. Nothing good ever comes of it. Hating evil is the only time such feelings could be positive.
The ארחות צדיקים takes this subject a step further, with a very specific warning. He cautions us to be aware of people who express words of love with their mouths. And yet, in their hearts they are filled with hatred. We must keep away from such people in the worst way.
Perhaps this is another important message of Purim. Not only must we be careful with the outside enemies of the Jewish people, but we must also be careful with the enemies from within. When we are aware of the hatred-how ever camouflaged, we will be protected and will see salvation. Purim Sameach