Psalm 110:1 & 4 (NIV)
The Lord says to my lord:
“Sit at my right hand
    until I make your enemies
    a footstool for your feet.”
The Lord has sworn
    and will not change his mind:
“You are a priest forever,
    in the order of Melchizedek.”

Who was Melchizedek? Read in Hebrews 7:15-28
https://www.biblegateway.com/passage/?search=Hebrews+7%3A15-8%3A2&version=NIV   

Psalm 109:30-31 (NLT)
I will give repeated thanks to the Lord,
    praising him to everyone.
For he stands beside the needy,
    ready to save them from those who condemn them.