The Lord God of Old Testament Israel is a unique Lord, a Jehoovaah ’Echaad [in the Hebrew].3 While the word yaachid in that language usually denotes absolutely indistinguishable and incongruously monolithic unity (cf. "together" or yachdaav in Deuteronomy 22:10-11) – on the other hand, the word ’echaad4 is often used to express a composite yet harmonious unity.
E.g., one bunch containing several individual grapes (’eshkol ^a:naavim ’echaad in Numbers 13:23) Or a man and his wife who, while yet retaining their own two bodies and distinctly different personalities, in sexual intercourse become one flesh (bassaar ’echaad in Genesis 2:24). That then sometimes results in yet a third distinct body and different personality (viz. that of their child) – each of which then, imaging one and the same God, is a created reflection of the Trinity. Genesis 1:26-28 & 2:22-24.