Bullies should be forewarned: King Solomon says in Ecclesiastes 3:15, "And G-d shall seek the pursued." In other words, Hashem will come to the aid of the bullied and punish the bully when he least expects it. Rabbenu Bachiya explains that this principle is so strong, that Hashem despise bullies so much, that if even a righteous person bullies an evil person, Hashem will come to the aid of the evil person and settle the score with the righteous person (see Rabbenu Bachiya on Vayikra 22:27).
Hashem loves compassion and kindness, yet hates bullying. True faith means loving what Hashem loves and depising what He despises. It is therefore a mitzva to despise bullies and to come to the aid of the bullied, no matter who they are and where they are.