Psalm 110, a "royal" psalm, establishes two functions for the king: ruler and priest. It is the most frequently quoted psalm in the New Testament, and early Christians viewed the psalm as testimony to Jesus as Messiah--the one who sits at the right hand of God (as we say often in the words of the Apostles' Creed).
But today, let's read Psalm 110 on its own terms. Psalms for All Seasons notes that the "intertwining of political, military, and priestly roles in one person [the Davidic king] suggests the importance of achieving integrity between worship and life." There is, then, no division between one's sacred life and one's secular life.
Do you feel division between your "Sunday" and your "Monday" self? In what ways is it hard to maintain integrity between worship and the rest of your life?
Psalm 110
1 The Lord says to my lord, “Sit at my right hand until I make your enemies your footstool.”
2 The Lord sends out from Zion your mighty scepter. Rule in the midst of your foes.
3 Your people will offer themselves willingly on the day you lead your forces on the holy mountains. From the womb of the morning, like dew, your youth will come to you.
4 The Lord has sworn and will not change his mind, “You are a priest forever according to the order of Melchizedek.”
5 The Lord is at your right hand; he will shatter kings on the day of his wrath.
6 He will execute judgment among the nations, filling them with corpses; he will shatter heads over the wide earth.
7 He will drink from the stream by the path; therefore he will lift up his head.