The crowning act of genesis was the creation of man, where G-d declared, “Let us make man.”
Our sages comment on the use of the plural “Let us”, even though G-d alone created man as the verse later states, “And G-d created man in His image”. This was done in order to teach a profound lesson, as if to say that He sought out the advice of the ministerial angels before creating man.
Now, given the infinite wisdom of the Creator, seeking advice was obviously unnecessary, and yet, the Torah writes that He did so only to show that regardless of how wise a person may be, he should always be ready to seek out and listen to the advice of others, even if they are less learned. A person who is vain and thereby has an insatiable ego is likely to consider accepting council from anyone as degrading and demeaning.
A haughty person, not only fails to benefit from the opinion of others, but by rejecting this interpretation of “Let us make man” is left with no alternative but to explain the words “Let us” as referring to a plurality of gods, because if the Creator was not seeking the advice of His inferiors, he must have been requesting the participation of an equal.
The Talmud equates vanity with idolatry. When a person indulges in self adoration, he sees no greater purpose in life than gratifying his own ego and his preoccupation with himself becomes essentially self-worship.
~ Rabbi Shaul