Monotheism

A distinction has to be made between exoteric and esoteric monotheism

Exoteric Monotheism is a particularily persuasive and widespread worldview, possibly because it is easy to anthropomorphise the supreme Reality into an external creator deity, most often male, a projection perhaps of patriarchial chieftains or a parental father into a sort of supernatural father figure

Although literal monotheistic belief may be useful for the spiritual development of those with particular personalities that require such belief, this sort of religious structure is tragically frequently associated with attitudes of intolerance, persecution, and arrogance

It is interesting to consider that materialism and capitalism are in fact natural outgrowths of monotheism - e.g. Lutheran biblical rationalism, the Calvinist work ethic, etc.  But still one has to concede that perhaps this was a  necessary stage that human consciousness had to go through, for without materialism and capitalism there might not have been the industrial revolution and  technological development of the West in the last two centuries

Exoteric Monotheism and (Esoteric) Monism

Esoteric Monotheism acknowledges the same scriptural authority as exoteric monotheism, but emphasises instead the "spirit of the law", rather than the "letter of the law".  The sacred text - whether Bible, Qu'ran, Gita or whatever is interpreted symbolically, as a sort of spiritual hermeneutics.  Moreover, deity, rather than being seen as an anthropomorphic or dualistically distinct figure, is conceived of monistically as the one indwelling life and essence of all things.  According to Ibn Arabi for example, the affirmation of Islam - there is no God but God - means esoterically there is no Being but (the Absolute) Being

Esoteric Monotehism is the basic approach of both Sufism in the Islamic tradition, Kabbalah in the Jewish, and some forms of Christian Hermeticism (Christian Cabala etc) in the (broadly) Christianit tradition.