How do we know the doctrine of the Antichrist is true?

The doctrine of the Antichrist is validated through scripture and historical observation. In 1 John 2:18, John explicitly states that there are many Antichrists, affirming that opposition to Christ has existed since the early church and continues today. This doctrine serves as a warning to believers about the spirit of opposition against the truth of Christ, which can manifest in various forms, including false teachings and moral failures. As Christians, understanding this doctrine helps us remain vigilant and anchored in the truth of the Gospel, identifying any teachings that do not align with sound doctrine.