AFTER the death of Solomon, the nation of Israel was divided into two kingdoms: the Southern Kingdom called Judah (Yehuda) ruled by Solomon’s son, Rehoboam, and the Northern Kingdom called Yisrael ruled by Jeroboam. You can read all about it in 2 Kings ch. 17.
The Northern Kingdom soon fell into gross immorality and paganism. Jeroboam didn’t want his subjects going to Jerusalem to worship, so he began the tradition of going to Shechem to worship. Jeroboam had two golden calves made for the people to worship. He told the people, “It is too much for you to go up to Jerusalem. Behold your gods, O Israel, who brought you up from the land of Egypt.” 
Things went badly. Kings would arise, and promote idolatry. Prophets would arise to warn the king and the people, very few of which would repent. For those who did not change their evil ways, judgment fell.
Decades later, in about 722 BCE, Assyria conquered the Northern Kingdom of Israel, and deported most of the residents of Israel to various Assyrian provinces, and brought deportees from other conquered territories to Samaria to take the place of the Israelites.
This was common practice among the Assyrians. Captive peoples who were deemed disloyal to the king were dispersed to different parts of the Assyrian Empire, where they could do no harm. He brought a host of peoples from other nations into the Northern Kingdom, and they possessed Samaria and lived in its cities. We read in 2 Kings 7:24-26:
“24And the king of Assyria brought men from Babylon, and from Cuthah, and from Ava, and from Hamath, and from Sepharvaim, and placed them in the cities of Samaria instead of the children of Israel: and they possessed Samaria, and dwelt in the cities thereof.
25And so it was at the beginning of their dwelling there, that they feared not the LORD: therefore, יְהֹוָה sent lions among them, which slew some of them.
26 Therefore, they spoke to the king of Assyria, saying, ‘The nations which you have removed, and placed in the cities of Samaria, do not know the manner of the God of the land: therefore He has sent lions among them, and, behold, they slay them, because they know not the manner of the God of the land.’ ”
At that time, the king of Assyria gave the order to bring one of the kohanim (priests) into the land to teach them about the “customs of the god of the land.” One of the kohanim came and “taught them how they should fear the LORD (2 Kings 7:28).”
The unfortunate result was that “every nation still made gods of its own and put them in the houses of the high places which the people of Samaria had made.”
However, “They feared YHWH and served their own gods according the to the custom of the nations from among whom they had been carried away into exile.”
As we read in 2 Kings 7:41: “So while these nations feared YHWH, they also served their idols. Their children and their grandchildren likewise: As their fathers did, so do they to this day.”
This is called syncretism, where you take two opposing philosophies, traditions, or religions, and then attempt to merge them together. This merger, or syncretism, was very displeasing to Adonai. One of the Ten Commandments is, “Thou shalt have no other gods before Me.”
As time went on, a people known as Samaritans arose. They are considered to be “half-breed” Israelites, a mixture of people from both the northern and southern parts of Israel, as well as a concoction of the other nations that the Assyrians brought to the Northern Kingdom. Modern-day Samaritans have their own version of Judaism, with their own version of the Torah, written in their own Samaritan script. They rejected the Temple in Jerusalem, and have their spiritual capital in Shechem, where they still sacrifice Passover lambs each year. They have, however, rejected the pagan deities. The Jews and Samaritans of Yeshua’s time did not like each other. This mutual dislike is now history. However, Samaritans in Shechem (Nablus) have a precarious existence among the Arab population.
Syncretism in Christianity
When I was a brand-new believer in Yeshua, fresh from the hippie counter-culture, I was horrified by the signs for “XMAS TREES.” Why would they ‘X’ out Christ? My opinion was that they should put Christ back into Christmas. What I did not know was that “Christ” was never in Christmas.
The pagan deities could not defeat the church, so they joined the church. Mythraism (the worship of Mythra—the sun god) was very popular 2000 years ago. Mythra even had a special day of the week in which people would worship him, on Sunday. Early Christians had their day of worship on Shabbat – the seventh day of the week. Eventually Emperor Constantine supposedly became a Christian. He convened the Council of Nicaea in 325 CE. This church council decided that Christians would no longer honor the Sabbath of the Jews, but would have their very own set apart day on Sunday. The very origin of Sunday as a holy day comes from paganism.
Christmas trees, wreaths, etc., all have pagan origins. Yeshua was likely born in the autumn, not December 25. This date was regarded as the birthday of Mythra. On December 25, many ancients were able to reckon that the days were getting longer again on December 25. Therefore, it was also called Natalis Solis Invicti, the birth of the unconquered Sun. This same date is also called Saturnalia.
In much the same way, we see how Christianity has coopted paganism in the holiday of Easter. The very name ‘Easter’ comes from the Babylonian goddess of fertility, named Ishtar.
According to Babylonian legend, the goddess Ishtar came down to earth in a giant egg. The egg hatched, and out popped Ishtar. Now you know the reason for Easter eggs. Since Ishtar was the goddess of fertility, we have the Easter Bunny.
Our Heavenly Father does not approve of such mixture religion. People often think of Messianic Judaism as a syncretic religion, as a mixture of Judaism with Christianity. In truth, the faith of Yeshua’s talmidim (disciples) was still Judaism. Yeshua did not come to start a new religion. He came as the Messiah for the old religion: Judaism. This faith of the First Century would today be called Messianic Judaism.
Prior to Acts chapter 10, the assumption was that Gentiles would first have to convert to Judaism in order to accept Yeshua. After all, Yeshua was the Jewish Messiah! However, God gave both Shimon Kefa (Peter) and Cornelius (a Roman centurion) simultaneous visions that ultimately led to Cornelius and the members of his household to faith in Yeshua.
Jewish believers of the First Century were called Natzratim (Nazarenes) in Acts 24:5, sect of the Way (HaDerech) in Acts 22:5, or simply Jews as in Acts 22:3. Jewish believers were not called Christians. In Acts 11:20, some Jewish believers experimented sharing the Besorah (Good News) with Gentiles in Antioch, and many of these Gentiles came to believe in the Jewish Messiah! The very first people to be called Christians were these Gentile believers in Antioch, in Acts 11:26.
When Rav Sha’ul (Paul) preached in the synagogues, he also encountered many gerim (proselytes to Judaism, as well as mamy other Gentiles who were attending the synagogues of his day, as we see in Acts 13:43; 14:1; 17:4; 17:17; and 18:4. In Acts 15:20, the Council at Jerusalem proclaimed a minimal amount of Torah-observance for these new Gentile believers, including prohibition of idol worship, sexual immorality, and meat from strangled animals. However, in Acts 15:21 (the very next verse!), we read, “For Moses from ancient generations has in every city those who preach him, since he is read in the synagogues each Shabbat.” In the First Century, these Christians were expected to incorporate the mitzvot (commandments) as they learned more from what they learned in the synagogues each week.
Eventually, the Gentile church grew to be much more numerous than the number of Jewish believers. Unfortunately, along with growth came syncretism, as the Gentile church incorporated pagan customs and traditions. We know from Malachi 3:4 that the LORD does not change. We also see in Hebrews 13:8 that Yeshua is “the same yesterday, today, and forever.” In other words, the syncretism that God opposed 2700 years, He still opposes.
I believe that many Christian pastors are aware of the syncretism that has infested the church. However, it is much easier to not rock the boat, so they go along with it. Even instituting something as simple as incorporating Shabbat can topple the boat. Churches that decide to observe Shabbat instead of Sunday often lose most of their members.