The bible said for we shall not have any other God except him, because he will never share his glory with anybody, and also the bible said we should not be equally yoked with unbelievers.
God cannot behold iniquity because he is a holy God, even before we come close to him we must be cleansed by the blood of the lamb. In the word today many has made so many things there God today without knowing it's idol they are worshiping, and some do it intentionally just like what the children of Israel did by creating a golden image they were worshiping which angered the lord because he clearly made us to know that he is a jealous God.
We have to know that we only have one true God and no other God except him. So anything outside God is idol. So therefore God does not listen to idol worshipers but he listens to those who made him there only God. Except they turn there ways from idol worshiping which is an iniquity in the site of God. There are so many things we do today that symbolizes idol worshiping that we don't know for e.g what ever you worship apart from God is Idol be it human being, material things.
So we must only worship God so that he would listen to our prayers.