Our Lord is the ultimate power--he is the one who places men and women in authority and gives them power, nomatter how much they think they are self-made or self-important. I noticed the phrase "today I have begotten you." My bible (The HarperCollins Study Bible, NRSV) notes that the phrase was part of the adoption of kings, whereby they are made God's sons. But it also points back and ahead to the King of Kings, eternally begotten of the Father, who alone can embody the chronological paradox (at least in English) of "today I have begotten you."
Today may I have the humility to bow before the authorities set over me and so be conformed to the character of Christ, who died for my sins.