Hear, O Israel:
The LORD our God is one LORD.
Deuteronomy 6:4
"The name “LORD,” of course, is Yahweh, or Jehovah, the self-existing One who reveals Himself, while “God” is Elohim, the powerful Creator/Ruler. “Jehovah our Elohim is one Jehovah” is the proclamation.
A number of respected Jewish commentators have acknowledged that the verse spoke of a “unified oneness” rather than an “absolute oneness.” The revered book called the Zohar, for example, even said that the first mention was of the Father, the second one the Messiah, and the third the Holy Spirit.
The key word “one” (Hebrew achad) is often used to denote unity in diversity. For example, when Eve was united to Adam in marriage, they were said to be “one flesh”.
Thus, Israel’s great declaration should really be understood as saying, in effect: “The eternally omnipresent Father, also Creator and Sustainer of all things, is our unified self-revealing Lord." ICR