Jamie Blosser of Ad Limina Apostolorum is doing us all the favor of offering summaries of St. Augustine's commentaries on the Sunday Gospel readings. Coming up: the parable of the Good Samaritan, for which St. Augustine offers a mystical exegesis:
The 'man' for St. Augustine is none other than Adam, representative of all of humanity; 'Jerusalem' is the heavenly city, representing his original state of justice and free-will; his falling into the hands of robbers represents his falling into sin, under the persuasion of the devil, and his resulting forfeiture of immortality and condemnation to death. The priest and Levite represent the priesthood and ministry of the old covenant, which proved unable to remedy his fallen condition. The Good Samaritan, of course, is Christ Himself, who alone is able to save: His binding of the wounds, the forgiveness of sin; the oil and wine, the comfort of hope and the encouragement to work. The beast upon which man is hoisted is the Incarnation, the enfleshment of the Word, by which man is raised up to share in the divine nature. The inn - you guessed it - is the Church where man recovers from the sickness of sin under the influence of the medicine of grace, and the innkeeper is - you didn't guess this - the Apostle Paul. The two silver coins are the dual commandments of love of God and neighbor (which Christ affirmed immediately before giving this parable) (cf., Quaest. Evan. 2.19; Hom. 31; Hom. 81).
I love this sort of stuff. It hints at the bottomless depths of meaning in Scripture.
The human response to Revelation is not memorization but creative engagement. If you meet someone who tells you, "I grew up on a farm," you don't reply, "You grew up on a farm," you ask, "What was that like?" And you know that what it meant for him to have grown up on a farm will not be exhausted in a two or three minute answer.
But did Jesus "really" intend the donkey of the parable to signify the Incarnation? That's probably not a well-formed question. Jamie explains St. Augustine's approach to exegesis:
The ultimate standard for such interpretation, for St. Augustine, is once again the law of charity. An interpretation is useful (n.b. he does not say 'correct,' but 'useful') inasmuch as it inclines the reader to the love of God and neighbor.
"Useful" is the strongest claim I should make about any commenting I do on Scripture, which isn't exegesis so much as conversation sparked by reading a passage from the Bible.
In any case, if Scripture is God's revelation to man, it necessarily contains an infinite meaning, and in reading it we should feel free to let our conversation with God wander where it will, knowing that when we wander from charity we are no longer speaking with God.