Then, it seems, "the Lord our God" wasn't "one God." He may have even had a wife
But compare Mark 10:8

καὶ ἔσονται οἱ δύο εἰς σάρκα μίαν: ὥστε οὐκέτι εἰσὶν δύο ἀλλὰ μία σάρξ

and the two shall be one flesh. So they are no longer two but one flesh.

John 1:14,
καὶ ὁ λόγος σὰρξ ἐγένετο

and the word became flesh