Verse from Leviticus

不可报复，也不可向你的族人怀恨，却要爱你的邻舍好象爱自己；我是耶和华。(利未记 19:18)

“‘Do not seek revenge or bear a grudge against anyone among your people, but love your neighbor as yourself. I am the Lord. (Leviticus 19:18)

Hanging on to bitterness and keeping alive grudges is consuming work. It leaves little energy for blessing others, praising God, or enjoying life. The only way to get over a bitter heart toward others is to actively love and serve them in ways that bless their lives. 

Remember, holding bitterness and keeping alive grudges doesn't cause others to suffer, you are the one who suffers in the end.