The 'Samaritans' of Jesus' day were strictly monotheistic, were located around Shechem, had maintained their own version of the Pentateuch, and had their own Temple and priesthood based on mount Gerizim (not on Samaria). It is likely that they were a Jewish sect. It is very unlikely that they were the products of the polytheistic religion found in Samaria as described by the prophets.
“In Samaria, north of Jerusalem, lived a Gentile people whom
the Jews of Christ’s day spurned, calling them ‘dogs.’
They had been moved there from areas of the Babylonian Empire about 700 b.c.
by various kings, including Shalmaneser of Assyria (2Kings 17:18, 21-24, etc.).”
The people of Samaria then were not Israelites; they were largely Babylonian by birth.
After Israel was taken into captivity, people from five Babylonian tribes were moved into Samaria.
They brought their Babylonian and Assyrian gods and their pagan practices with them.
Soon after possessing the land, these Babylonians were attacked by lions (verse 25).
The new colonists superstitiously believed that the lion attacks were coming upon them
because they had failed to honor the god of the new land (verse 26).
They failed to recognize that God had sent Israel into captivity because of their idol
worship. and this land was still very importent to God, even when no Israels lived there.
The newly settled Samaritans asked the Assyrian king to send back a priest from Israel
to teach them how to worship the God of the land. The king complied (verse 27),
but what they received was a priest who taught them the pagan practices of northern Israel.
Thus, they were taught a religion of Old Testament teaching mixed with paganism.
The Samaritans began to worship Israel’s God using the false teachings of
the evil King Jeroboam. Remember, Jeroboam was an outright rebel.
He formed his own religion. He forced true priests of God to flee to Jerusalem
and Judea (2Chronicles 11:14). He established calf worship at Dan and Bethel
(1Kings 12:28-30).
He changed the fall holy days from the seventh to the eighth month.
He made priests of the lowest of the people, those who were not of the tribe of Levi
(verse 31).
So the Samaritans were deeply deceived by an Israelite priest who taught them
pagan practices while showing them God’s name.
They began to refer to themselves as the people of God, but essentially they
remained Babylonian idolaters (2 Kings 17:41). “They brought with them into
the land of Samaria their own Babylonian mystery religion.
In the eighth chapter of Acts you’ll read of their religious leader in
the time of Christ, Simon Magus the Sorcerer” ,
Exposing Simon Magus, that Simon “used sorcery, and bewitched the
people of Samaria, giving out that himself was some great one:
To whom they all gave heed, from the least to the greatest, saying,
This man is the great power of God” .
These verses reflect more than just an ordinary encounter with a man
converting to Christianity.