What has God been doing for the last nineteen hundred years?
For the last nineteen hundred years, God has been primarily calling out Gentiles to comprise the Body of Christ, after Israel rejected their Messiah and God dispersed them. This Gentile calling forms the Church, the Body of Christ, during this age.
Les explains that after Israel finally rejected their Messiah completely and would not have Him as King, God put them into dispersion, took away their temple, and turned to the Gentiles. Not exclusively, because some Jews are still being saved, but for the most part, the last 1900 and some years have been God calling out Gentiles to comprise the Body of Christ. Les prefers to view the book of Acts primarily as the fall of the nation of Israel, even though it is also the birth of the Church. During this period, Israel falls away, the Gentiles come up, and the Church is coming up.