"To be a good Jew does not necessarily mean believing in God, just doing what He says."However, if one does not believe in the existence of this so-called 'god', why would one pay any heed to the sayings that are attributed to it?
The Rabbi attempts to circumlocute his way around this fundamental flaw in his argument by claiming that all that is necessary [to be a Jew] is to follow what is considered to be their so-called god's most important command, viz: “Love your neighbour as yourself” (Leviticus 19) or, as Hillier reformulated it in the 1st century, "Do not do to others what you would not have them do to you” - sometimes referred to as 'the Golden Rule' - yet treating others in a way that one would like them to treat oneself almost certainly pre-dates the anthropomorphic entity that theists have invented and graced with the name of 'god'.
Nevertheless, the Rabbi's argument has some merit, in that it is a de facto an acknowledgement that it is not necessary to believe in 'god' to live a moral and decent life, something that many other theists have extreme difficulty in accepting and regularly accuse atheists of being incapable of morality, ethics, compassion, empathy,love, art, literature, aesthetics, or any of the other so-called 'higher' emotions that they arrogantly ascribe to themselves alone.
However, I must contradict the good Rabbi: someone who does not believe in your 'god' may still be a Jew in your opinion but they are, by definition, an atheist in anyone else's.