"An angel called to him from heaven and said, 'Abraham, Abraham!'" (Gen. 22:11)

[Why does the angel repeat Abraham's name?] Because every tzadik in this world has two souls, one in this world and one in the World to Come. So one finds with every tzadik [that at one point or another in the Torah, his name is repeated]: "Moses, Moses"; (Ex. 3:4) "Jacob! Jacob!"; (Gen. 46:2) "Samuel! Samuel!"; (Samuel I 3:4) "Shem! Shem!". (Gen. 11:10)

The only exception is Isaac, whose name is not written twice like the others, for when Isaac was offered on the altar his this -Worldly soul left him. When Abraham said, "Blessed is the One Who brings the dead back to life," only Isaac's soul from the World to Come returned to him. Therefore we find that the Holy One, blessed is He, did not assign His Name to anyone [living in this world] other than Isaac, because he was regarded as dead [in this World, and living in the World to Come].[Zohar I, p.60a] From the day that Moses was born he was perfect….

When a name is mentioned twice [in the Torah], there is a psik ta'ama [a cantillation note which requires the reader to pause between the first and second mention of the name] between them, such as "Abraham! Abraham!", "Jacob! Jacob!", "Samuel! Samuel!" However, "Moses Moses" is written without a psik ta'ama between the two. What is the reason?

[Regarding the verse] "Abraham! Abraham!" the latter is complete, [i.e. it indicates that Abraham had reached perfection,] for he passed all ten trials with which he was tested; whereas the former [indicates that he was as yet] incomplete. That is why there is a psik ta'ama between the names: Now he was not the same as before. [Similarly], "Jacob! Jacob!" the latter is complete, for it was announced that Joseph [was alive], after which the Shechina [once again] dwelt upon Jacob, while the former is not. Furthermore, now in the Land [of Israel] the Holy Tree [Jacob] became complete, reflecting the [world] above [Zeir Anpin which has] twelve dimensions [the Twelve Tribes, corresponding to all the possible permutations of the Ineffable Name] and seventy branches [which correspond to the seventy souls which accompanied Jacob down to Egypt. (See Ex. 1:5. It is possible that seventy also represents the state of tikun (full rectification) of the sefirot of Zeir Anpin and malchut - 7x10, where each of the seven sefirot contains all ten of the sefirot.)]

Jacob did not have this before. Since the latter [name "Jacob" indicates] completion [or perfection], whereas the former does not, there is a psik ta'ama between them. Also "Samuel! Samuel!" has a psik ta'ama between the names. Why? Because the latter [indicates] perfection, whereas the former does not. [At a certain point], he became of prophet; prior to this he was not. However, "Moses Moses" is written without a psik ta'ama between the two, [for] from the day that Moses was born he was perfect, as it is written, "And she [Moses' mother] saw that he was good" (Ex. 2:2)

[Zohar III, 138a; translation and commentary by Moshe Miller
First published by Fiftieth Gate Publications and Seminars.]