The book of Jeremiah is very helpful with answering your excellent question. Jeremiah was a prophet to the people of Judah. When Jeremiah lived, the nation of Israel had already been divided into the Kingdom of Israel and the Kingdom of Judah. Jeremiah spoke from the Lord to the people of Judah about their sins, pleaded with them to repent, and announced the Babylonian captivity that would occur if they did not repent. Concerning Judah’s sins and the reason for the coming captivity, we read in Jeremiah 16:10-13, “Now when you tell this people all these words, they will say to you, ‘For what reason has the LORD declared all this great calamity against us? And what is our iniquity, or what is our sin which we have committed against the LORD our God?’  Then you are to say to them, ‘It is because your forefathers have forsaken Me,’ declares the LORD’ and have followed other gods and served them and bowed down to them; but Me they have forsaken and have not kept My law. You too have done evil, even more than your forefathers; for behold, you are each one walking according to the stubbornness of his own evil heart, without listening to Me. So I will hurl you out of this land into the land which you have not known, neither you nor your fathers; and there you will serve other gods day and night, for I will grant you no favor’” (NASB).

Part of worshipping other gods was adopting the practices of the surrounding nations. We read in Jeremiah 9:25-26, “Behold, the days are coming,” declares the LORD, “that I will punish all who are circumcised and yet uncircumcised— Egypt and Judah, and Edom and the sons of Ammon, and Moab and all those inhabiting the desert who clip the hair on their temples; for all the nations are uncircumcised, and all the house of Israel are uncircumcised of heart” (NASB). The house of Israel had been physically circumcised, but they were spiritually uncircumcised in their hearts. They were worshipping other gods and adopting the mourning practices of the pagan nations around them. One of those practices was clipping the hair on their temples.

The Lord had commanded the people of Israel not to adopt these pagan practices. In addition to Leviticus 19:27, we read in Leviticus 21:5-6, “They shall not make any baldness on their heads, nor shave off the edges of their beards, nor make any cuts in their flesh. They shall be holy to their God and not profane the name of their God, for they present the offerings by fire to the LORD, the food of their God; so they shall be holy” (NASB). This instruction is repeated in Deuteronomy 14:1-2, which says, “You are the sons of the LORD your God; you shall not cut yourselves nor shave your forehead for the sake of the dead. For you are a holy people to the LORD your God, and the LORD has chosen you to be a people for His own possession out of all the peoples who are on the face of the earth” (NASB).

The reason for the commands in Leviticus 19:27 is that the Lord wanted the people of Israel to be a holy people separated unto Himself. He loved them so much that He disciplined them for rejecting Him. Jehovah’s great love for the people of Israel is described in Deuteronomy 7:7-8, which states, “The LORD did not set His love on you nor choose you because you were more in number than any of the peoples, for you were the fewest of all peoples, but because the LORD loved you and kept the oath which He swore to your forefathers, the LORD brought you out by a mighty hand and redeemed you from the house of slavery, from the hand of Pharaoh king of Egypt.” He loved them because He loved them, and He loves us with the same unconditional love as well!

Applying this topic to our lives today, we know that we are not under the law of Moses. We read in Romans 6: 14, “For sins shall not have dominion over you: for ye are not under the law, but under grace.” However, God still wants us to be holy and separated unto Himself. We read in 1 Peter 1:16, “Because it is written, ‘Be ye holy; for I am holy.’” We also read in 2 Corinthians 6:14-18, “Do not be bound together with unbelievers; for what partnership have righteousness and lawlessness, or what fellowship has light with darkness? Or what harmony has Christ with Belial, or what has a believer in common with an unbeliever? Or what agreement has the temple of God with idols? For we are the temple of the living God; just as God said, ‘I will dwell in them and walk among them; and I will be their God, and they shall be my people. Therefore, come out from their midst and be separate,’ says the Lord. ‘And do not touch what is unclean; and I will welcome you. And I will be a Father to you, and you shall be sons and daughters to Me,’ says the Lord Almighty” (NASB).  (DJ)  (734.3)