Abraham father of Monotheism

The Rabbis teach us that Abraham spread the belief of One God in the Universe. The rabbis also tell us that Abraham rejected his father Terach's idol practices. The problem I have is it is all medrash, where in the Torah is there any hint that Terach was an idol worshipper. With aid of Gematria, we have a clue. Where can we find this clue? We have to connect the two parshiyos between Noach and Lech Lecha. The last words of Noach says, vayamas terach becharan, or and Terach died in Haran. This equals 1324. The first four words of Lech Lecha says, vayomer Hashem el avram lech lecha. This phrase equals 657. If you add this up, it equals 1981. 1981 equals a phase in Leviticus 19:4, where it says,   Turn you not to idols,  nor make yourselves molten gods, I am the Lord your God.
Gematria is one of the 32 methods of studying the Torah. This is concrete proof that Terach was an idol worshipper and by God telling Abraham to leave his father, leave his homeland, leave his place of birth, God was telling Abraham to reject that lifestyle.



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