Why twelve? Why not eight? Why not twenty-four? The number twelve was filled with symbolic importance. There were twelve tribes in Israel. But Israel was apostate. The Judaism of Jesus’ time represented a corruption of the faith of the Old Testament. Israel had abandoned divine grace in favor of works-religion. Their religion was legalistic. It was shot through with hypocrisy, self-righteous works, man-made regulations, and meaningless ceremonies. It was heretical. It was based on physical descent from Abraham rather than the faith of Abraham. In choosing twelve apostles, Christ was in effect appointing new leadership for the new covenant. And the apostles represented the new leaders of the true Israel of God – consisting of people who believed the gospel and were following the faith of Abraham (cf. Romans 4:16). In other words, the twelve apostles symbolized judgment against the twelve tribes of Old Testament Israel.
John MacArthur