The Wisdom of Jesus the Son of Sirach, or Ecclesiasticus 38:5 주석

The passage records an ancient episode, when the children of Israel “walked three days in the desert of Shur and did not find water. They arrived” finally “at Marah, but they could not drink the waters of Marah, because they were bitter.” But the Lord “pointed out a piece of wood” to Moses, and when he “threw it into the water, it became sweet.” According to the account, the power of God was manifested there through his medical science, in the waters made sweet by the wood. And the mystery of this event is obvious. The people grumble, seeing the waters and being unable to drink. Moses throws the wood into the waters, and they become sweet. Understand that the bitter waters represent the letter that kills and the Law. If one throws on this the confession of the cross and adds the mystery of the passion of the Lord, then the bitter water becomes sweet, and the bitterness of the letter is transformed into the sweetness of spiritual knowledge. For this reason it is written, “The Lord established a law and judgments for his people, and he tested them.” According to another sense, the bitter waters that become sweet by receiving the wood are an image of the bitterness of the nations over the wood of the cross of Christ, which at a certain point is destined to become sweet.