Vos on Kingdom: "God Will Intervene"
"The difference between the two stages of its coming does not lie in that the one is brought about by forces already present in the human world, whereas the other has to be accomplished by the introduction of new miraculous forces from above. It is a difference merely in the mode of operation and revelation of the supernatural common to both stages. The same omnipotent power at work through the ages will also effect the consummation at the end. But it will assume a new form when the end has come, so as to work instantaneously, and will draw within the sphere of its operation the entire physical universe. It would not be in harmony with Jesus' view so to conceive of it, as if by the gradual extension of the divine power operating internally, by the growth of the church, by the ever-widening influence of the truth, the kingdom which now is will become all-comprehensive and universal and so of itself pass over into the final kingdom. This would eliminate all true eschatology and obliterate the distinction between the two aspects of Jesus' teaching on the subject.
"The parables of the wheat and the tares and of the fishnet, while on the one hand they do imply, as we have seen, the higher unity of the entire movement, also imply on the other hand that its consummation does not spontaneously result from the preceding process, supernatural though this be. The harvest is conditioned by the ripeness of the grain, and yet the ripeness of the grain can never of itself set in operation the harvest. The harvest comes when the man puts forth the sickle, because the fruit is ripe. So when the immanent kingdom has run its course to maturity, God will intervene in the miracle of all miracles. It would also plainly be impossible for the final kingdom to come in any other way than this, For this final state of the kingdom presupposes great physical, cosmical changes, which no force working in the spiritual sphere can produce. It would be difficult to overestimate the vividness with which our Lord realized and the emphasis with which he describes the new and marvelous conditions under which the life of the blessed in the future kingdom will be lived. It is an order of things lying altogether above this earthly life, in which the righteous shall shine as the sun, in which all the prophets will be seen, in which the pure in heart shall enjoy the beatific vision of God, in which those who hunger and thirst after righteousness shall be completely filled. Surely to effect this there must take place a great crisis, a great catastrophe at the end which will be the very opposite of all evolution. Our Lord himself has marked its unique character by calling it the palingenesis, the regeneration, Matt. 19: 28." -- Geerhardus Vos, "The Teaching of Jesus Concerning the Kingdom of God"