Eternal security is a theological concept primarily associated with certain branches of Christianity, particularly within Protestantism. It asserts that once a person has genuinely accepted Jesus Christ as their Savior, they are guaranteed salvation and cannot lose it, regardless of future actions or sins. This belief emphasizes the grace of God and the permanence of His promises. Proponents of eternal security often reference biblical passages, such as John 10:28-29, which speaks of believers being held securely in God's hands. Critics, however, argue that this view may lead to complacency in moral behavior, suggesting that faith should be accompanied by ongoing commitment and repentance.