you shall be My witnesses

Acts 1:8 (NASB)
...  but you will receive power when the Holy Spirit has come upon you; and you shall be My witnesses both in Jerusalem, and in all Judea and Samaria, and even to the remotest part of the earth."
From A.W.Tozer,
" You know the Church started out with a Bible , then it got a hymnbook, and for years that was it- a Bible and a hymnbook. The average church now certainly wouldn't be able to operate  on just a hymnbook and the Bible. Now we have to have all kinds of stuff. A lot of people couldn't serve God at all without at least a vanload of equipment to keep them happy."