This is the association and idolatry.
But the truth is: No god but God alone without associate or equal.
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Well said Prophet Joseph son of Jacob, when he was in the prison, before he became prime minister of Egypt; as in the Quran 12: 37-40 which mean:
{37. f[They said to him: Which of these idols is your Lord? He said:] "I have forsaken the religion of a folk [who are associaters: worshipping the idols with God, and] who believe not in God [alone g] and [moreover] of the Next Life they are deniers. h "
38. "And I have followed the religion of my fathers: Abraham, Isaac and Jacob; we ought not to associate anything with God i; that is [some] of God's bounty to us and to people j, but most of people give no thanks [about God’s bounties to them.]"k
39. "O my two companions in prison, which is better: many differing lords [of stone, silver and copper which neither harm nor profit, or is God: the One, the Omnipotent l?"
40. "You worship none, apart from [God], other than mere names which you and your fathers have named, concerning which God has not revealed any authority m.
The decision [about the worship] is up to God [alone] n. He has commanded [in the heavenly books] that you should worship none other than He [alone].
That o is the religion of [Prophet Jacob] the guardian [on his sons and his people], but most of people do not know [the truth.]"}
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f They said to him: Which of these idols is your Lord; so guide us to him, in order that he may acquaint us about the interpretation of the dream, as has he taught you?
So he said: (I have forsaken the religion of a folk who believe not in God [alone.])
g But they associate with Him.
h i.e. they deny the sending of souls to the Next Life and the Judgment.
i Therefore, we do not worship idols and statues.
j Who devote themselves to God alone.
k So this was his answer to their question: “Who is your Lord?” Therefore, he said to them: I don’t worship any idol, neither did my fathers worship the idols, but we worship God the Lord of the heavens and the earth. It is He Who taught me about the interpretation of dreams. Then if you want to be like myself, then worship God alone and refrain from worshipping the idols, and He will give you all that you want.
Then he said to them:
l Who revives and kills, and by Whose hand is everything?
m It means: The idols which you worship and to which you give names; such names are devoid of meaning, and are not true; moreover, God did not reveal any commandment in any heavenly book to worship the idols.
n It means: It is not allowed that anybody may worship anyone according to his own desire, but it should only be according to God’s commands in the heavenly books.
o i.e. That which I have explained to you, concerning the worshipping of God alone and forsaking the worship of idols …
The interpretation is by Mohammed-Ali Hassan Al-Hilly.