The Midrash relates an aspect of the story about which most people are unaware. It says that 30 years earlier the tribe of Ephraim “forced the hour” and started out before the appointed time, and when the rest of the people finally left, they found the bones of the Ephraimites in heaps along the way (Sh’mot Rabba chapter 20).
In Jewish history there were countless occasions when Jews wanted to take the law into their own hands and get away from a nightmare before the destined time of dawn. This certainly applies to the coming of Messiah, which never seemed to arrive even though we could hardly bear the waiting.
The Meshech Chochmah, commenting on a statement by Rashi, actually speaks about an early coming of Mashi’ach. Parashat Shof’tim (Deut. 19:9) has a verse about three extra “cities of refuge” for those who commit homicide without intent; Rashi says this applies to the days of Mashi’ach. The Meshech Chochmah says Rashi denotes the Mashi’ach coming before the set time.
If Israel lead such committed lives that God sends the Mashi’ach early, it will take time to finish eradicating sin, crime and murder. The Mashi’ach will lend his weight to the effort, and once it is complete the days of perfection predicted by the prophets will finally arrive.