Exodus第4章:25

For the Israelitish church to represent spiritual things, it would have to be in external actions only, because the people at that time had no real idea of the Lord or love for him or for other people. This is the deal made by Zipporah, who represents people of the Ancient Church who did still have such internal worship.

Using a flint to cut off her son’s foreskin represents using teachings from the Lord to remove external falsities and evil from the ideas being passed to the Israelitish church - basically forbidding the people to act on their evil desires. This exposed the internal state of the Israelites, which was also evil, but would allow the Lord to impose forms of external worship and ritual on them. Touching the foreskin to her son’s feet (some translations say it was Moses’s feet, but the original language indicate it was the baby’s) represents the idea that these things would be done on an external, natural level, since that is the meaning of the feet.

Finally, Zipporah calls Moses a "bridegroom of blood" (again, some translations say "husband," but "bridegroom" is closer to the original language). In the highest sense, a "bride" represents the church and a "bridegroom" the Lord - but this is not the highest sense. Zipporah does represent the true church, but as a "bridegroom of blood" Moses represents the evil that was in the hearts of the Israeli people, and the actual violence they felt toward the good things they would represent.

It is hard in some ways to hear the Children of Israel described in such harsh terms. We’re used to thinking of them as the "chosen" people, as the ones who followed Jehovah, the true God. But if we consider how often and how easily they slipped into idolatry and the casual cruelty so often reflected in their stories, it’s not so hard to believe that their "chosen" status had little to do with the kinds of people they were, and more to do with what they represented in the bigger spiritual history of the human race.