I've read a lot of Psalms recently and been asking questions about them. Here are some conclusions.
I've been asked several times why Psalm 95 is prayed every morning in the Liturgy of the Hours. The last two stanzas are somewhat frightening:
Today listen to the voice of the Lord
Do not grow stubborn as fathers did in the wilderness
When at Meribah and Massah they challenged me and provoked
Although they had seen all of my works.
Forty years I endured that generation
I said they are a people who hearts go astray
They do not know my ways
So I swore in my wrath
They shall not enter into my rest.
The answer came in reading Hebrews, I don't know why I never noticed it much before. Read Hebrews 3 and 4. Chapter 3 explains why the Israelites did not enter: unbelief. Chapter 4 concludes that there is still hope for us while it is still today. A very good reminder at the beginning of the day.
Next one is Psalms 58:10:
The righteous will rejoice when he sees the vengeance;
he will bathe his feet in the blood of the wicked.
That you may bathe your feet in blood.
The first Psalm there is actually excluded from the current Liturgy of the Hours on account of being possibly psychologically disturbing. The literal context would have to do with battle with those persecuting the author. Bathing with blood sounds pretty bizarre, but there is one place in the Books of Kings that talks about harlots bathing in Ahab's blood. Anyway...
St. Augustine in interpreting this passage says that when we see wicked people punished ("bleeding") for doing evil, then we must ourselves learn ("bathe our feet", or hands in Augustine's text) the consequences of such actions so as to more effectively avoid sin. Also, since St. Augustine's text said hands instead of feet, he may not have seen a possible connection with the washing of the feet in the Gospels (both Mary Magdalene of Jesus, and Jesus of the Apostles). I don't see a connection yet, but I'll be thinking about it in the near future...