“The security of the believer” is a theological expression based on Scriptural revelations underlying the doctrine of assurance While this doctrine is rejected by some, others find it of great spiritual value to accept without question what the Bible teaches about the safekeeping of the people of God.
The believer’s life in Christ is said to be everlasting or eternal — that is, it will never end, John 3:16; Rom. 6:23. Believers shall never perish, neither shall any man pluck them out of the Father’s hand, John 10:28, 29. They are said to be “kept by the power of God,” 1 Pet. 1:5; kept for Jesus Christ, Jude 1, RV. Christ declared that all who believe have everlasting life, and shall not come into condemnation, John 5:24. He is able “to save them to the uttermost that come unto God by him,” Heb. 7:25.
The entire Trinity is involved in the safekeeping of Christians. The Father has given believers to the Son, John 17:9. The Son has asked that they be kept, John 17:11, 20. The Holy Spirit is to dwell within every believer forever, John 14:16; 1 Cor. 6:19. These revealed truths have nothing to do with human experience, but only with the divine purpose and promise. Passages which seem, to some, to contradict the doctrine of security are found to be related to rewards, chastisement, and the fact that an absence of good works reveals a lack of genuine faith, Phil. 2:12, 13; 2 Pet. 3:9-17.
William Evans, The Great Doctrines of the Bible, (Chicago: Bible Institute Colportage Assoc., 1912), WORDsearch CROSS e-book, Under: “Security”.