# because of the surpassing greatness of the revelations

"because those revelations were so much greater than anything anyone else had ever seen"

# a thorn in the flesh was given to me

"God gave me a thorn in the flesh" or "God allowed me to have a thorn in the flesh"

# a thorn in the flesh

Here Paul's physical problems are compared to a thorn piercing his flesh. Alternate translation: "an affliction" or "a physical problem" 

# a messenger from Satan

"a servant of Satan"