## the whole world ##

This is an exaggeration referring to the world they knew, which in this context is the Roman Empire.

## For God is my witness ##

Paul wants to add emphasis that he earnestly prays for them and God has seen him praying. The word "for" is often left untranslated.

## I make mention of you ##

"I talk to God about you"

## always in my prayers requesting that...I may be successful...in coming to you ##

"Every time I pray, I ask God that...I may succeed...in coming to visit you"

## by any means ##

"in whatever way God allows"

## at last ##

"eventually" or "finally" or "in the end"

## by the will of God ##

"because God desires it"