"Hear, O Israel: The LORD our God, the LORD is one (Echad)."
(Deuteronomy 6;4).
This word Echad means one but it does not nessesarily mean one ALONE. Rabbi Tovia Singer said that it is like if I say "I have one penny in my hand" this does not mean there's only one penny in the universe. So yeah the other pennies are DIFERRENT they are not the same penny which I have!!
So if this is what it mean then Deuteronomy 6;4 was saying that God is one so this mean that either there are more DIFERRENT gods or it was referring to one person in trinity (father) because the word one cannot be used to refer to multiple things at the same time so this mean only father is God and other two persons are DIFERRENT gods according to the meaning of the word Echad!! Because if I say I have ONE penny in my hand then this does not mean the other pennies are same pennies which I have!! So if the word Echad does not mean one ALONE then it prove that either Trinity is wrong or the word Echad do not prove trinity at all!!
If anyone got my point then please put this in a better way.
