Psalm 3

1

A song of David when he ran away from his son Absalom: 

O Great I AM! So many have become my enemies! So many have turned against me!

The book of Samuel tells us Absalom thought about chasing David with only 12,000, and that 20,000 on Absalom's side were lost in battle. It must have been some force going against David!

2

They talk about me, saying, "Even God won't help him."

Selah

We have no idea what "selah" means. It appears to be some sort of musical term, but there are good arguments for it meaning anything from "pause in silence" to "play very loudly" to "change keys" to "the string instruments play a solo here." We just don't know.

3

But You, Great I AM, are a shield around me, my glory and honor, the One who removes my shame, so I can hold my head up 

I took a bit liberty with this verse's translation. It literally says "the lifter of my head," which, in modern English, is a tiny bit vague. 2 Samuel 15:30 tells us David ran away from Absalom with his head bowed in shame. Now, David is giving God credit for removing his shame so he can hold his head up in public again. He "is the lifter of David's head."

4

I cry to You out loud, I AM, and You hear me from Your holy hill. Selah 

5

So I can sleep peacefully and wake up in the morning (refreshed), because you, I AM, take care of me.

The original doesn't have any words equal to "refreshed," but it fits the context. It conveys David's trust in the Lord.

6

I will not be afraid of the tens of thousands of enemies who surround me.

7

Rise up, O Great I AM! Save me, my God! Punch my enemies in the face! Break the wicked's teeth! 

8

Salvation only comes from the I AM! Bless your people, God. Selah 

We serve the same God David did. He is just as available to defend us against our enemies.