James Trimm’s Commentary on Sh’mot Chapter 14

14:19-21

19 And the angel of Elohim, who went before the camp of Yisra’el, removed, and went behind them. And the pillar of cloud removed from before them, and stood behind them.
20 And it came between the camp of Egypt and the camp of Yisra’el. And there was the cloud and the darkness here, yet gave it light by night there: and the one came not near the other all the night.
21 And Moshe stretched out his hand over the sea. And YHWH caused the sea to go back by a strong east wind all the night, and made the sea dry land, and the waters were divided.
(Exodus 14:19-21 HRV)

The Bahir quotes Rabbi Berachiah as teaching:

110. There is a name that is derived from the three verses (Exodus 14:19-21) , “And traveled … And came … And stretched…” The letters of the first verse, “And traveled…” are arranged in this name in the order that they are in the verse. The letters of the second verse, “And came …” are arranged in the name in reverse order. The letters of the third passage, “And stretched…” are arranged in the name in the same order as they occur in the verse, just like the case of the first verse. Each of these verses has 72 letters. Therefore, each of the names that is derived from these three sentences, “And traveled… And came… And stretched…” contains three letters. These are the 72 names. They emanate and divide themselves into three sections, 24 to each section. Over each of these sections is a higher Officer. Each section has four directions to watch, east, west, north and south. The four directions then have a total of 24 forms. [This is true of the first section] as well as the second and the third. All of them are sealed with YHVH , God of Israel, the living God, Shaddai, high and exalted, who dwells in eternity on high, whose Name is holy, YHVH. Blessed be the name of the glory of His kingdom forever and ever.

There are 72 Hebrew letters in each of these verses. If we write these verses out one right under the other boustrophedonically (as the ox plows), the first line left to right, the second line right to left, and the third line left to right again, we produce 72 columns of three letters each, or 72 three letter names known as the Shemhamforesh.

See comments to Exodus 23:20-23 and Malachi 3:1