Exodus 15:25

25. The Lord showed him a tree Many have supposed that this tree had sweetening properties, possibly neutralizing the salts which made the water undrinkable . Some have suggested that Moses used the ghurkud berries, above mentioned, for this purpose . But it was not yet time for this berry, which ripens in June, while the Israelites were at Marah in April; and if there were any shrub or tree in the desert possessing natural properties which would make these bitter, brackish springs drinkable, it is not at all probable that so valuable a fact would be unknown to the natives of the region; yet diligent inquiries made by the most intelligent travellers have failed to find any such knowledge among the Bedouins .

It is most probable that the wood had no more healing virtue than the clay which Jesus applied to the eyes of the blind man, or the Jordan waters which cleansed the leprosy of Naaman. The tree was but the appropriate means to call forth faith. Casting it into the waters was an exercise and manifestation of faith. And this was an instructive “sign” as well as a miracle. The first judgment-stroke upon Egypt made the sweet, wholesome Nile waters loathsome, and the first saving miracle in the desert made sweet the bitter Marah. Luther’s typical application is excellent. “Moses causes man to murmur by the terrors of the law, and thus pains him with bitterness, so that he longs for help; and then, when the Holy Spirit comes, at once it [the law] is made sweet. Now this tree of life is the Gospel, the word of the grace, the mercy, and goodness of God. When the Gospel is plunged into the law, and into the knowledge of sin which the law produces, and when it touches a heart in which the law has caused sadness, anxiety, terror, and confusion, it is at once delightful to the taste.”

For them (or, him, Israel being personified as one man) a statute and an ordinance, and there he proved them (or, him; the pronoun is grammatically singular) The statute or law, and the ordinance or judgment, follows in the next verse.