Rather, that the things which the Gentiles sacrifice they sacrifice to demons and not to God, and I do not want you to have fellowship with demons.
1 Corinthians 10:20
What says 1 Corinthians 10:20 can be seen from different angles. If we look at the time, there is a direct message to the Christians in Corinth to warn the pagan practice of sacrificing to false gods. At present, although the cult of Zeus or Apollo is discontinued, there are people who still offer sacrifices and promises to saints, which somehow make them idols. On the other hand, you should always see the spiritual aspect of the Scriptures. Try to make a sacrifice, yet it is to the true God, it is to subtract validity to the sacrifice of Jesus on the cross.
In ancient times it was common to offer blood sacrifices to the deity in which they believed. The Bible itself review the animal sacrifices demanded by the true God to the people of Israel. In the ancient pagan world, every people offered blood sacrifices to their gods. In some cultures these sacrifices included human beings. What Paul says in 1 Corinthians 10:20 that the sacrifices of the Gentiles were directed to test the hell that the devil has always tried to imitate the things of God and the blood sacrifices to idols were part of his imitation of sacrifices God gave to His people.
In modern times, who openly worship Satan are the ones who continue to practice blood sacrifices. This practice is very common among followers of Santeria and voodoo and other manifestations of demon worship. However, since such sacrifices are not practiced within Judaism, mainly because there is no temple since almost two thousand years ago. Other religions today not make them.
Although within call themselves Christians who have never performed blood sacrifices, yes there are certain practices that fall well within what Paul had admonished the Corinthians. Trying to repeat the sacrifice of Jesus on the cross, either through an authorized by a church or by common practice in places like the Philippines to hang on a cross at Easter rite are not sacrifices directed to God but to demons who seek to steal the glory of God and His Son Jesus Christ.
Other common sacrifices especially in some Latin American countries practiced by followers of traditional religion are offering promises to images in paid for alleged miracles. Such promises include, among others, wear a certain color for some time, stop eating any food at a specific time, give special alms to the image, bring candles, walking barefoot or on their knees to the shrine of the image, etc. All these practices will never sacrifice addressed to God but the devil behind every image, which robs His glory to the Most High.
Finally, certain “Christian” churches practice a kind of sacrifice frankly as demonic as above. These are called “covenants with God,” which usually involve the provision of a sum of money, which supposedly God will multiply a hundredfold. Indeed this kind of sacrifice is not directed to the true God but a demon named Mammon, the god of money. The real sacrifice as Jesus did on the cross of Calvary in atonement for the sins of all. Right there He sealed with His blood the new covenant through which we receive forgiveness when we acknowledge His Lordship in our lives. To do anything else is nothing but a mockery of Him. God bless you.