The book
To the Emperor Gratian.
The choice of Gideon was a figure of our Lord's Incarnation, the sacrifice of a kid, of the satisfaction for sins in the body of Christ; that of the bullock, of the abolition of profane rites; and in the three hundred soldiers was a type of the future redemption through the cross. The seeking of various signs by Gideon was also a mystery, for by the dryness and moistening of the fleece was signified the falling away of the Jews and the calling of the Gentiles, by the water received in a basin the washing of the apostles' feet. St. Ambrose prays that his own pollution may be washed away, and praises the loving-kindness of Christ. The same water sent forth by the Son of God effects marvellous conversions; it cannot, however, be sent by any other, since it is the pouring forth of the Holy Spirit, Who is subject to no external power.
1. When Jerubbaal, as we read, was beating out wheat under an oak, he received a message from God in order that he might bring the people of God from the power of strangers into liberty. Nor is it a matter of wonder if he was chosen for grace, seeing that even then, being appointed under the shadow of the holy cross and of the adorable Wisdom in the predestined mystery of the future Incarnation, he was bringing forth the visible grains of the fruitful grain from their hiding places, and was [mystically] separating the elect of the saints from the refuse of the empty chaff. For these elect, as though trained with the rod of truth, laying aside the superfluities of the old man together with his deeds, are gathered in the Church as in a winepress. For the Church is the winepress of the eternal fountain, since from her wells forth the juice of the heavenly Vine.
2. And Gideon, moved by that message, when he heard that, though thousands of the people failed, God would deliver His own from their enemies by means of one man, offered a kid, and according to the word of the Angel, laid its flesh and the unleavened cakes upon the rock, and poured the broth upon them. And as soon as the Angel touched them with the end of the staff which he bore, fire burst forth out of the rock, and so the sacrifice which he was offering was consumed. By which it seems clear that that rock was a figure of the Body of Christ, for it is written: “They drank of that rock that followed them, and that rock was Christ.” Which certainly refers not to His Godhead, but to His Flesh, which watered the hearts of the thirsting people with the perpetual stream of His Blood.
3. Even at that time was it declared in a mystery that the Lord Jesus in His Flesh would, when crucified, do away the sins of the whole world, and not only the deeds of the body, but the desires of the soul. For the flesh of the kid refers to sins of deed, the broth to the enticements of desire as it is written: “For the people lusted an evil lust, and said, Who shall give us flesh to eat?” That the Angel then stretched forth his staff, and touched the rock, from which fire went out, shows that the Flesh of the Lord, being filled with the Divine Spirit, would burn away all the sins of human frailty. Wherefore, also, the Lord says: “I have come to send fire upon the earth.”
4. Then the man, instructed and foreknowing what was to be, observes the heavenly mysteries, and therefore, according to the warning, slew the bullock destined by his father to idols, and himself offered to God another bullock seven years old. By doing which he most plainly showed that after the coming of the Lord all Gentile sacrifices should be done away, and that only the sacrifice of the Lord's passion should be offered for the redemption of the people. For that bullock was, in a type, Christ, in Whom, as Esaias said, dwelt the fullness of the seven gifts of the Spirit. This bullock Abraham also offered when he saw the day of the Lord and was glad. He it is Who was offered at one time in the type of a kid, at another in that of a sheep, at another in that of a bullock. Of a kid, because He is a sacrifice for sin; of a sheep, because He is an unresisting victim; of a bullock, because He is a victim without blemish.
5. Holy Gideon then saw the mystery beforehand. Next he chose out three hundred for the battle, so as to show that the world should be freed from the incursion of worse enemies, not by the multitude of their number, but by the mystery of the cross. And yet, though he was brave and faithful, he asked of the Lord yet fuller proofs of future victory, saying: “If You will save Israel by mine hand, O Lord, as You have said, behold I will put a fleece of wool on the threshing-floor, and if there shall be dew on the fleece and dryness on all the ground, I shall know that You will deliver the people by my hand according to Your promise. And it was so.” Afterwards he asked in addition that dew should descend on all the earth and dryness be on the fleece.
6. Some one perhaps will enquire whether he does not seem to have been wanting in faith, seeing that after being instructed by many signs he asked still more. But how can he seem to have asked as if doubting or wanting in faith, who was speaking in mysteries? He was not then doubtful, but careful that we should not doubt. For how could he be doubtful whose prayer was effectual? And how could he have begun the battle without fear, unless he had understood the message of God? For the dew on the fleece signified the faith among the Jews, because the words of God come down like the dew.
7. So when the whole world was parched with the drought of Gentile superstition, then came that dew of the heavenly visits on the fleece. But after that the lost sheep of the house of Israel (whom I think that the figure of the Jewish fleece shadowed forth), after that those sheep, I say, “had refused the fountain of living water,” the dew of moistening faith dried up in the breasts of the Jews, and that divine Fountain turned away its course to the hearts of the Gentiles. Whence it has come to pass that now the whole world is moistened with the dew of faith, but the Jews have lost their prophets and counsellors.
8. Nor is it strange that they should suffer the drought of unbelief, whom the Lord deprived of the fertilising of the shower of prophecy, saying: “I will command My clouds that they rain not upon that vineyard.” For there is a health-giving shower of salutary grace, as David also said: “He came down like rain upon a fleece, and like drops that drop upon the earth.” The divine Scriptures promised us this rain upon the whole earth, to water the world with the dew of the Divine Spirit at the coming of the Saviour. The Lord, then, has now come, and the rain has come; the Lord has come bringing the heavenly drops with Him, and so now we drink, who before were thirsty, and with an interior draught drink in that Divine Spirit.
9. Holy Gideon, then, foresaw this, that the nations of the Gentiles also would drink by the reception of faith, and therefore he enquired more diligently, for the caution of the saints is necessary. Insomuch that also Joshua the son of Nun, when he saw the captain of the heavenly host, enquired: “Are you for us, or for our adversaries?” lest, perchance, he might be deceived by some stratagem of the adversary.
10. Nor was it without a reason that he put the fleece neither in a field nor in a meadow, but in a threshing-floor, where is the harvest of the wheat: “For the harvest is plenteous, but the labourers are few;” because that, through faith in the Lord, there was about to be a harvest fruitful in virtues.
Source: On the Holy Spirit (New Advent)