The symbolism of Jeremiah 10 is briefly explained in this excerpt from our Bible study aid Holidays or Holy Days: Does It Matter Which Days We Observe?:

Regrettably, the Israelites failed to permanently heed God's warning. Time and time again they let their fascination with the religious practices of those around them get the better of them as they lapsed into idolatrous worship.

Around 600 B.C. God gave three more warnings against this kind of behavior. First, through the prophet Jeremiah, God said, 'Do not learn the way of the Gentiles; do not be dismayed at the signs of heaven, for the Gentiles are dismayed at them' (Jeremiah 10:2). Here God cautioned His people against following the gentile (non-Israelite) practices of worshiping the heavenly bodies (like the sun on Dec. 25) and against astrology in general.

In the following verses (Jeremiah 10:3-5), God describes some of their idolatrous customs. They cut a tree from the forest, shaped it with an ax and overlaid it with precious metals. Although this account is specifically referring to the making of an idol (Jeremiah 10:6-8), God's command, 'Do not learn the way of the Gentiles,' applies to all pagan customs. Christmas trees, mistletoe and colorful lights that come from pagan winter-solstice celebrations, rabbits and Easter eggs as fertility symbols, and demonic concepts at Halloween, all fit this prohibition. In giving this instruction against learning the way of the gentiles, God wanted His people to avoid the type of sin their forefathers had committed with the golden calf.

A more extensive explanation of Jeremiah 10 is found in the UCG Bible Commentary:

In this chapter, God makes it very clear: "Learn not the way of the heathen...for the customs of the peoples are vain" (Jeremiah 10:2-3, KJV), stressing His total rejection of practices adopted from other religions even if they are intended to honor Him. For God is never honored by disobedience. We can read Deuteronomy 12:29-32 and 2 Corinthians 6:14 along with these verses.

God first points out here that pagans were "dismayed at the signs of heaven" (Jeremiah 10:2). As believers in astrology, they considered their lives to be controlled by celestial events. Today, it is no different among the huge number of people who make daily decisions based on their horoscopes. This practice is utterly condemned by God. Even if astrological forces existed—which they do not—the Almighty Creator and Ruler of the universe would have power over them.

Worse still, the sun, moon, planets and stars were actually worshiped by ancient nations—and their movements were used to determine times for worship. Again, this was all based on fear and superstition. For instance, the winter solstice was observed because the sun reached its lowest zenith on that day, the shortest day of the year. It was believed that worship, fires and sacrifices were needed to encourage and boost the sun god back to his higher station. Afterward, the people celebrated the rebirth of the sun.

Indeed, the sun god was understood to have been born of his mother goddess around the time of the winter solstice—in fact, by the reckoning of various ancient cultures, on December 25. Evergreen plants and trees were used in this particular worship because they seemed to retain life through the winter months. These customs have continued down to our day in the form of the Christmas tree and decorations of holly and mistletoe.

Continuing then in Jeremiah 10:3-5, at least in the King James, New King James or Jewish Publication Society translations, the Christmas tree must surely come to mind. However, many mainstream Christian scholars, and other Bible versions, identify the objects addressed in this section as wooden poles or idols. That is certainly possible. In fact, it may even be likely if the word translated 'workman' in Jeremiah 10:3 can only mean a skilled craftsman and if the word translated 'ax' here can mean a carving tool, as some have rendered it. The exact meaning of the verse remains unclear.

Interestingly, it should be noted that the Hebrew word translated 'wooden idol' in Jeremiah 10:8, ets, is normally translated 'tree' in the Bible. Notice God's instruction back in Deuteronomy 16:21: 'You shall not plant for yourself any tree [ets], as a wooden image [asherah], near the altar which you build for yourself to the LORD your God.'

There are a number of references in Scripture to Asherah—understood to be an idol representation of the goddess Ashtoreth or Astarte, the mother goddess referred to in Scripture as the 'queen of heaven' (mentioned in the highlights on Jeremiah 7:1-27). 'From the Biblical references, it appears that Asherah is referred to in three manifestations: (1) as an image, probably a statue or figurine representing the goddess herself; (2) as a tree; and (3) as a tree trunk. The latter two are, in effect, symbols of the goddess' (Ruth Hestrin, 'Understanding Asherah: Exploring Semitic Iconography,' Biblical Archaeology Review, Sept.-Oct. 1991, p. 50). Indeed, the phrase 'under every green tree' (Deuteronomy 12:2), is used a number of times in Scripture to denote a pagan sacred place—that is, not just trees but evergreen trees.

Jeremiah 10 is indeed talking about the setting up of idols. But what many fail to realize in reading through the chapter is that sometimes trees themselves were set up by ancient pagans as idols. Depending on the exact meaning of the words translated workman and ax in the chapter, a carved idol or an actual tree could be meant. Both were cut from the forest, with stands fashioned to keep them fixed and upright but still able to be moved and set up anywhere (Jeremiah 10:3-5). Both, in the ancient world, were decorated with silver and gold and draped with costly fabrics (Jeremiah 10:4 and Jeremiah 10:9). With tree idols, idolatrous metal ornaments were sometimes fashioned and hung from the branches—which Jeremiah 10:9 could be describing. Yet the verse could alternatively be a reference to metal adornments for a carved idol.

In direct disobedience to God, the Jews under Manasseh actually set up an asherah in honor of Baal, the son and husband of Ashtoreth (see 2 Kings 21:3). Indeed, such was used in surrounding cultures to honor the sun-god Baal and his mother on the birthday of the sun, December 25—which is when this abomination of Manasseh may have taken place, in imitation of neighboring societies. Even if that's not exactly what Manasseh did, it is rather likely that such decorated trees in winter would have been part of the Jews' worship of Baal, as in other cultures.

More amazing to consider is the fact that in the syncretistic blending of religions, Baal ('Lord') was identified with the true Lord. Thus, the apostate Jews, in copying pagan worship customs, may well have set up decorated evergreen trees to worship the birthday of the true Lord—the One who later came to earth as Jesus Christ! And the Lord called their adoption of such customs to honor Him an abomination. Indeed, He still does.

While people today do not worship trees when they set up Christmas trees or other evergreen decorations such as holly and mistletoe, they are nevertheless using accoutrements of past idolatry to supposedly honor God. Yet the true God will have none of it. He sees it as disobedience and rebellion—and idolatrously clinging to tradition over His direct commandments. For anything that comes before the true God is an idol, whether we literally bow down to it or not. Indeed, it is even possible that modern Christmas trees are intended by Jeremiah's words—particularly when we consider that this may be, as it seems to be on some level, an end-time prophecy to the 'house of Israel' that speaks of God's coming wrath on the nations and the destruction of all idolatry (compare Jeremiah 10:1, Jeremiah 10:10-11, Jeremiah 10:15). For in the end time, the Israelite nations are not setting up wooden Asherah poles. But every winter, there are millions and millions of Christmas trees. And even if Christmas trees are not directly intended by the prophecy, the principle is the same.