It is not Biblical. Nowhere in the Bible does it say that there are multiple gods. God never commands Polytheism.
Oh it's all over the place, it is saturated with Gods a plenty!
Gen 1
"And the Eohim/Gods said, Let
us make man in
our image, after
our likeness: ....So God created man in his own image, in the image of the Gods created he him; male and female created he them."
Gen 3
And the Lord God said, Behold, the man is become as one of
us, to know good and evil:
Ps 82
1 God standeth in the congregation of the mighty; he judgeth among the gods.
6 I have said, Ye are gods; and all of you are children of the most High.
Deut 32 RSV This passage explains what the original belief/truth was
7 Remember the days of old, consider the years of many generations; ask your father, and he will show you; your elders, and they will tell you.
8 When the Most High gave to the nations their inheritance, when he separated the sons of men, he fixed the bounds of the peoples according to the number of the sons of God.
9 For the LORD's portion is his people, Jacob his allotted heritage.
and we will add in Heb 1 which is quoting Ps 45
8 But unto the Son he saith, Thy throne, O God, is for ever and ever: a sceptre of righteousness is the sceptre of thy kingdom.
9 Thou hast loved righteousness, and hated iniquity; therefore God, even thy God, hath anointed thee with the oil of gladness above thy fellows.
Abraham to Moses well up until around 600 bc this was all understood as truth.
According to Hebrew very ancient (true) myths there were 70 sons of El. Yahweh was the firstborn and he was chosen above his fellows. He was anointed God by his God, his title was Lord of host, Lord of lords and God of gods. Which meant he was over all the other sons of God. The nations of the earth were divided up between these lesser gods to be their mediators between them and Yahweh. All but for Jacob's family the nations were two steps away from El, first they would petition their son of God, this lesser son would petition Yahweh and he then would petition El. Yahweh as Lord of host was mediator between the seventy sons and El. This is what was going on in Job 1 when the sons of El come to present themselves before Yahweh. Satan also comes among the sons of El.
Now comes in my own speculations, Satan wasn't directly kick out of heaven. We see him in Job 1 and in Zach 3 doing his calling of giving opposition. But, as time went on he became more and more envious. He too want to be worshiped and so did these other 70 sons. Thus the war in heaven increased and they stopped going to present themselves before Yahweh, idol worship began because these rebellious sons led the hearts of men astray.
Now as we look at Isa 43 we can see it in a different light;
9 Let all the nations be gathered together, and let the people be assembled: who among them can declare this, and shew us former things? let them bring forth their witnesses, that they may be justified: or let them hear, and say, It is truth.
10 Ye are my witnesses, saith the Lord, and my servant whom I have chosen: that ye may know and believe me, and understand that I am he: before me there was no God formed, neither shall there be after me.
11 I, even I, am the Lord; and beside me there is no saviour.
The Lord is referring to this witnesses or the other sons of God and saying show us how they can justify, let them come forth and show their power. They can't for I alone was appointed or ordained God, there is no saviour beside me.
and then he says
25 I, even I, am he that blotteth out thy transgressions for mine own sake, and will not remember thy sins.
26 Put me in remembrance: let us plead together: declare thou, that thou mayest be justified.
If there is no other God then to whom is he pleading? As the mediator he pleads our case for us to the Father El.
In Hebrew tradition no one can declare their own authority including Yahweh. We see at the baptism of Jesus here the Father says 'This is my beloved Son, in whom I am well pleased'. We find this also in Isa 42 when and unnamed voices but we must logically assume is the Father declares;
1 Behold my servant, whom I uphold; mine elect, in whom my soul delighteth; I have put my spirit upon him: he shall bring forth judgment to the Gentiles.
2 He shall not cry, nor lift up, nor cause his voice to be heard in the street.
3 A bruised reed shall he not break, and the smoking flax shall he not quench: he shall bring forth judgment unto truth.
4 He shall not fail nor be discouraged, till he have set judgment in the earth: and the isles shall wait for his law
And then Yahweh declares his authority;
5 ¶Thus saith God the Lord, he that created the heavens, and stretched them out; he that spread forth the earth, and that which cometh out of it; he that giveth breath unto the people upon it, and spirit to them that walk therein:
In these passages we see all three members of the Godhead, El the Father, Yahweh and the Spirit. There are also indications that Shadday a female Goddess was worshiped and not as an idol but as a very real God.
"Even by the El of thy father, who shall help thee;
and by Shadday, who shall bless thee with blessings of heaven above, blessings of the deep that lieth under, blessings of the breasts, and of the womb" Gen 49. Her symbol of a tree which give live was placed in the Temple by Solomon and left there until after the Jews returned from exile.
Around 600bc and then after their return there began to be a changes. There was a movement called the Deuteronomists, they were a group of scribes and elite Jews who brought back with them from captivity the concept that Yahweh would be their only God. They got Josiah who was only 8 when he began his reign to remove Shadday's symbol from the temple and they merged El and Yahweh into one God. Malachi takes them to task for what they have done, they are not worshiping idols in their temple but they are worshiping a strange god.
"But ye are departed out of the way; ye have caused many to stumble at the law; ye have corrupted the covenant of Levi, saith the Lord of hosts.....Have we not all one father? hath not one El created us? Judah hath dealt treacherously, and an abomination is committed in Israel and in Jerusalem; for Judah hath profaned the holiness of the Yahweh which he loved, and hath married the daughter of a strange god" Mal 3
But not all Jews would worship this god, this strange god. Many of the common Jews worshiped Yahweh as the Son of El and they waited for him to come.
In John 1 we see;
Nathanael and the other members of John's little group of followers held on to the more ancient doctrines recognized Yahweh and said; Rabbi, thou art the Son of El; thou art the King of Israel.
Paul was a member of the elite and he persecuted those who taught he was the Son of God until he has his vision ;
"And straightway he preached Christ in the synagogues, that he is the Son of God. But all that heard him were amazed,..."
They were amazed because he left his former beliefs of only Yahweh and accepted Yahweh/Jesus as the Son of El.
Two Gods not one, two Gods who are one in purpose.