Psalms 61:1-8 NIV
Hear my cry, O God; listen to my prayer. From the ends of the earth I call to you, I call as my heart grows faint; lead me to the rock that is higher than I. For you have been my refuge, a strong tower against the foe. I long to dwell in your tent forever and take refuge in the shelter of your wings. For you, God, have heard my vows; you have given me the heritage of those who fear your name. Increase the days of the king’s life, his years for many generations. May he be enthroned in God’s presence forever; appoint your love and faithfulness to protect him. Then I will ever sing in praise of your name and fulfill my vows day after day.
This psalm was written by David. Some scholars suggest it was written at a time when he was not the king. Saul was the king, and he was after David's hide. Into that context David prays positively for the king. This is something that has a reflection of Jesus's teaching to pray for those who persecute you.
Personally, I am not really a monarchist; however, the prayer David offers for his king is one I can offer for King Charles. Praying that anyone would be in God's presence, that God's love and faithfulness bring protection, must be right.
Lord God may your love and faithfulness surround those who cause me the most problems. In Jesus's name. Amen.