Why did God destroy the temple and disperse Israel in 70 A.D.?
Because Israel rejected the Christ and continued rejecting the overtures Peter and the eleven made toward them. About forty years after the crucifixion, in 70 A.D., God saw fit to remove them from the land, permit the temple to be ruined and destroyed, and disperse the nation.
Les explains that God had previously removed Israel in His sovereignty—the ten northern tribes to Assyria, and the two southern tribes to Babylon for seventy years—but they returned and rebuilt the temple. Then, after they rejected Christ and kept rejecting all the overtures Peter and the eleven made, in 70 A.D., forty years after the crucifixion, God once again took them out of the land, allowed their temple to be ruined and destroyed, and they were dispersed. According to His promises, however, He is bringing them back from the four quarters of the world.