"But I say to you, love your enemies and pray for those who persecute you." (Matthew 5:44)
"...bless those who curse you, pray for those who mistreat you." (Luke 6:28)
Jesus instructed humanity to pray for those who mistreat us. And He also instructed us where to pray.
“...when you pray, go into your room and shut the door and pray to your Father who is in secret. And your Father who sees in secret will reward you." (Matthew 6:6)
The first thing we are to do in prayer is forgive those we are holding a grudge against.
"Don’t worry about anything; instead, pray about everything. Tell God what you need, and thank Him for all He has done. Then you will experience God’s peace, which exceeds anything we can understand. His peace will guard your hearts and minds in Christ Jesus. And now, dear brothers and sisters, one final thing. Fix your thoughts on what is true, and honorable, and right, and pure, and lovely, and admirable." (Philippians 4:6-8)