Cyril of Alexandria : The water was not life-giving. For they were not able to satisfy those who longed for truth from their teachings. Their tongues remained parched from thirst. But I will hear them, says the God of Israel, and I will not abandon them. For he had mercy on the mass of those who strayed and did not leave them without gifts from above, but rather he gave to them in fullness, and this in such a way as is finely described in the verses that follow.… The desert and the land short of water is the region of the Gentiles. The desert that will run dry and barren of any flowering growth, meaning spiritual growth, is the way of shriveling, where the wild trees are those useful only for burning in fire. The water allows the nations to bear fruit. To those who were once thirsty he says, "I will make rivers flow on the mountains," that is, holy people who are enriched by the divine word from above and pour out like flowing streams to the thirsty. — COMMENTARY ON Isaiah 3:5.41:16-20 Jerome : These varieties of trees signify the diversity of spiritual grace. And because the nature of them is well known to all, we will now explain the Setta, which Theodotio translated as a thorn. It is a type of tree that grows in the desert and resembles a white thorn. From this tree, all the wood for the ark and the tabernacle was made, which is called Settim (Exodus 37). This wood is incorruptible and very light, surpassing all other types of wood in both strength and beauty. But cedar and cypress, and myrtle, of excellent fragrance and incorruptible, are joined with elm and poplar, or with boxwood, or they are most suitable for grafting vines or for various works. All these things are placed together in solitude, so that at least one string of the Lord's lyre and some virtue of the Church's graces may not seem to be lacking. That all may understand and know together in their minds that the hand of the Lord has brought forth all these things, so that in the dryness of the nations the streams of virtues may be found, and in a once deserted and full of saltiness land, cedars and cypresses, and other trees may be born, whose height and top reaching toward the heavens would be illuminated by the wood of the olive, which is the nourishment of light and rest for those who labor. — Commentary on Isaiah