The psalm begins with an oracle: the Lord says to my Lord, sit at my right hand until I make your enemies a footstool for your feet. David, who is speaking, calls another Lord, whom God invites to take the place of honor. In verse 2 the Lord sends forth from Zion the scepter of his power and tells him to rule in the midst of his enemies.
Verse 3, a difficult text, says his people will offer themselves freely on the day of his power, in holy garments, and speaks of the dew of youth from the womb of the morning. In verse 4 the Lord swears and will not change his mind: you are a priest forever after the order of Melchizedek. Melchizedek was the king and priest of Salem who blessed Abraham in Genesis 14.
Verses 5-7 describe the King's action: the Lord at his right hand will shatter kings on the day of his wrath, execute judgment among the nations, fill the places with corpses and shatter chiefs over the wide earth. He will drink from the brook by the way, and therefore he will lift up his head.