Missionary Work

I read where the term "mission" properly refers to conversion from idols to the one true God.  Since Jews and Mainline Protestants already believe in the one true God, there should be no need to expend missionary zeal on converting them from their faith to the missionary's belief.  A lot of missionary zeal has been spent on doing exactly that, trying to convert believers.  Anti-Semitism and The Reformation fuel a lot of this zeal.  Maybe the zeal should be directed to idol worshippers such as Wall Street and top floor corporate types who worship money?  People tend to worship their addictions.  "More" is a modern god.  Alcoholics focus on booze, and do not come off it on a daily basis until they are converted to belief in a higher power.  Find the addicts in your world and mission to them.  Of course, you are not one of them.  Be still my heart.