http://revach.net/article.php?id=4286

Section: Parshas HaShavua   Category: Numbers & Letters
Parshas Shemos: Rav Shimshon MiOstropolia - Moshe's Gilgulim Appear In The Fire
When Moshe came to the burning Sneh, the Pasuk tells us, "Vayeira Malach Hashem Eilav BiLabas Eish; A Malach of Hashem appeared to him in a flame of fire (Shemos 3:2)."  Chazal cryptically tell us on this pasuk, "to complete his name."  What does this mean?

The Chida brings from Rav Shimshon MiOstropolia that Moshe was a gilgul of Hevel and Sheis, two sons of Adam HaRishon.  The name Moshe is the Roshei Teivos of Mem - Moshe, Shin - Sheis, and Hei - Hevel.  However Moshe's name still leaves the Suf of Sheis and the Bais and Lamed of Hevel unaccounted for.  The Malach came, "BiLabas Eish."  Labas is the missing letters Lamed, Bais, Suf.  With it Moshe completed his name and got his full power to do his Shlichus.

"Furthermore," says the Arizal, "we see this hinted in the Pasuk before.  It says that Moshe Haya Ro'eh Tzon.  Moshe was a shepherd.  It uses the past tense to teach us that not only was Moshe currently a shepherd, but also in his previous gilgul as Hevel, who the Torah says was a shepherd."