Saint Matthew’s Gospel records an interesting detail not found in the other Gospels. Here we read that Christ rode both the ass and her foal or a female donkey and her colt.
How did this work? Did Christ straddle both creatures at the same time. Of course not. According to Lapide, Christ first rode the ass up and down the mount and then rode the colt into the city.
There is a practical reason for this. The she-ass would be stronger and more able to go up and down the terrain. Next, the colt would be able to bring him into the city easily.
Yet there is a mystical signfication is this as well. The she-ass and her colt signify “the two sorts of people of which the world is made up—the Jews, accustomed to the yoke of the Mosaic law, who were represented by the ass; and the Gentiles, living up to this time without the Law of God, and who were denoted by the colt.”
The she-ass represents Mother Israel who has been burdened with the Law of Moses. Saint Peter our first Pope described the Mosaic Law as “a yoke…which neither our fathers nor we have been able to bear” (Acts 15:10, D-R).
The young colt represents the new and untrained Gentiles–the wild olive branch that the Apostle describes as the Gentiles.
Christ our Lord rode both to signify that both the Jews and the Gentiles were called to be Christophoroi - Christ-bearers.