What was the condition of Israel at the end of the 40-year period?
At the end of the 40-year period from the crucifixion to the temple’s destruction, Israel remained adamant in unbelief. Because of that unbelief, God permitted Rome to come in, destroy the city and temple, and send Israel into dispersion among all the nations of the world.
Les explains that the book of Acts covers this 40-year period, during which God is still dealing with His covenant people even as He begins going to the Gentiles. The 40 years was a period of testing, and at its end Israel was still adamant in unbelief. Therefore, the sovereign God permitted Rome to come in, destroy the city in the most awful siege in all of ancient history, destroy the temple, and send Israel into dispersion among all nations—a dispersion that has begun to end but has not yet fully ended for the most part.