The letter Mem [מ] symbolizes water and is associated with the number forty. If that
seems an odd pairing, we should consider that the first “forty” in scripture
denotes the duration of the Genesis flood in days. Thereafter, the number is
often associated with testing or judgment.
In the New Testament, water is most frequently associated
with the Holy Spirit of God. It is not without reason that we call that great,
singular event in which the Spirit came to indwell all who are in Christ and
bind together Jew and Gentile into one body a “baptism”. But water serves other
purposes than cleansing and testimony. It meets the perpetual need of humanity.
Jesus cried out to the thirsty, “Come to me and
drink.” John comments, “He said this about the Spirit.”
How does the Spirit operate in the human heart? Well, he
uses the word of God, which is where our psalmist comes in once again.