Deuteronomy 13

1 God had already spoken to several Hebrews in visions and dreams. Prophets and dreamers would continue to appear in Israel's history.
2 The fulfillment of their prophecies and dreams was generally evidence that their words came from God. However, if these prophets and dreamers encourage people to follow other gods, then they were to be ignored, no matter how convincing the sign or wonder.
3 Love for and obedience to God are to take precedence over all things. Nothing should be able to trick us or convince us to do otherwise. Our human perception is limited, and it is possible to be tricked and amazed simply because we do not see what is happening behind the scenes.
5 Following false gods is rebellion against God. Israel was also warned that the entire nation would suffer if they turned from God. Thus, if someone encouraged false worship, it was not just a "religious" offense; it was a capital offense against the nation. Israel's "constitution" was the Ten Commandments, and the violation of them often resulted in the death penalty.
7 This is a very inclusive list. The Israelites were familiar with the gods of Egypt and the gods of Canaan, but God foresaw the day when Israel would be exposed to "theisms" from all over the world. This would happen first when Israel became an important trading nation, and second when Israel would later be dispersed among the nations. God makes it clear that there is no other god, anywhere or at any time, that should be worshiped. He alone is God.
8 Worshiping other gods was such a serious offense that no one was protected from its consequences. It was each person's religious and social duty to expose false worship and purge it. This duty was even more important than family and friendship ties. They were not to simply ignore the person or try to protect them. They were not to have pity on them, because they had been warned about the consequences.
9 The person who found out about this offense was to take the lead in exposing the person and commencing their execution. Then the community was to join in the execution. This was to show the solidarity and agreement in the community that such an evil thing deserves the most severe punishment.
10 Stoning is a gruesome form of punishment, but it serves at least a few purposes here. It involves several people, which makes no "one" person responsible for the offender's death, thus eliminating the possibility of vengeance. The community agreement would also prevent vengeance. Stoning distanced the executioners from the offender, thus preventing defilement by contact.
11 Certainly, the punishment was so horrific that no one hearing about it would want to risk suffering the same fate. The severity of the punishment emphasizes the severity of the offense in God's eyes.

This law applied specifically to Israel since theocracy ("rule by God") was the basis for the Law. Today there are no theocracies, and, in fact, most governments are secular. Since most governments require at least some tolerance for other religions, the possibility of such a strict standard are eliminated.

Concerning Christianity, Jesus did not call us to "force" people to become Christians. Forced obedience does not encourage love for God. We are to try to win people with the Good News that Jesus died for their sins and wants them to have a positive relationship with Him.

Within the Christian community we do need to act when false worship is found. However, we are not called to execute the guilty party. They may be excommunicated, but even then, the hope is that they will turn back to God and be restored to the rest of the community. The Church becomes weakened when God's people become tolerant of false worship among them. We must love the people of this world and desire that they come to know God, but we must not compromise our beliefs or message in the process.