John assures us, “These things have I written unto you that believe on the name of the Son of God; that ye may know [present knowledge] that ye have [present possession] eternal life…” (1 John:5:13). If the person who had eternal life could lose it and suffer eternal death, to call it eternal life would be a mockery. On the contrary, eternal life is linked with the promise that one cannot perish—a clear assurance of “eternal security” or “once saved, always saved.” John:3:16 promises those who believe in Jesus Christ that they “shall not perish, but have everlasting life.” John:5:24 again says, “he that heareth my word, and believeth on him that sent me, hath everlasting life, and shall not come into condemnation.” One could not ask for clearer or greater assurance than the words of Jesus: “I give unto them [My sheep] eternal life and they shall never perish” (John:10:28).
If sin causes the loss of salvation, what kind or amount of sin does it take? There is no verse in the Bible that tells us. We are told that “if we confess our sins, he is faithful and just to forgive us our sins and to cleanse us from all unrighteousness” (1 John:1:9)—so apparently any sin can be forgiven. Even those who teach falling away rarely if ever say they got “saved again.” Rather, they confessed their sin and were forgiven. Hebrews:12:3-11 tells us that every Christian sins, and that instead of causing a loss of salvation, sin brings God’s chastening upon us as His children. If when we sinned we ceased to be God’s children, He would have no one to chastise—yet He “scourgeth every son whom he receiveth.” Indeed, chastening is a sign that we are God’s children not that we have lost our salvation: “If ye be without chastisement, whereof all are partakers, then are ye bastards, and not sons.”
Some teach that one must be baptized to be saved, others that one must “speak in tongues.” Both are forms of salvation by works. Some people lack assurance of salvation because they haven’t “spoken in tongues,” others are confident they are saved because they think they have. Both are like those who say, “Lord, Lord, have we not…in thy name done many wonderful works?” (Matthew:7:21-23). They are relying on their works to prove they are saved instead of upon God’s grace. Nor does Jesus say to these workers of signs and wonders, “You were once saved but lost your salvation.” He says, “I never knew you.” These are solemn words from the lips of Him who said, “I know my sheep” (John:10:14). If He never knew them, they were never His sheep.