Yesterday, I said that even though someone consciously believes the Gospel, it does not mean he is born-again. The devil believes, but he is certainly not a Christian (Jam. 2:19). Those professing to be Christians may actually believe the Bible's revelation of God through Jesus Christ, but rather than accept Him as Lord, all they do is join a "social club." In other words, they join a church but never become a child of God. The perfect example is the Church of Laodicea described as being very successful according to man's standards (rich, thriving, large numbers, etc.), but Jesus had no part in it; He is described as standing on the outside of it, knocking to get in (Rev. 3:14-22).
In "Can Christians Lose Their Salvation?" by Michael J. Penfold, he argues that because the salvation of a person is totally the work of God, it is not possible for a born-again believer to deny the truth. He wrote, "... the repentant sinner is sealed with, indwelt by, baptized in and anointed with the Holy Spirit (Eph. 1:13; Jn. 14:17; 1 Cor. 12:13; 1 Jn. 2:27). He receives eternal life (Jn. 3:36) and because he is now ‘in Christ’, he is predestined to be conformed to Christ’s image (Rom. 8:29)."
I have written often that salvation is a free gift; Jesus paid for my sin (2 Cor. 5:21), the Father drew me to Jesus (Jn. 6:44), and the Spirit gave me saving faith (Eph. 2:8-9). It is as though I was walking away from God (living as though I was a god), and I heard His voice softly call my name. I was "saved," I was "born again," I became a genuine Christian when I turned around (repented) and began following Him. In other words, when I acknowledged and accepted His amazing gift. I did not deserve salvation; it is the result of grace, the unmerited favor of God. Just an interesting side note: the same Greek root, χάρις (charis), is translated as both "gift" (Rom. 6:23) and "grace" (Eph. 2:8).
Genuine salvation produces the "fruit of the Spirit" (Gal. 5:22-23). Authentic regeneration results in good works (Eph. 2:10). The Apostle James put it this way in James 2:17-20, "Even so faith, if it hath not works, is dead, being alone. Yea, a man may say, Thou hast faith, and I have works: shew me thy faith without thy works, and I will shew thee my faith by my works. Thou believest that there is one God; thou doest well: the devils also believe, and tremble. But wilt thou know, O vain man, that faith without works is dead?" Just as works without genuine faith cannot save us, a faith that does not result in good fruit and good works, lacks evidence of salvation.
To sum up: a true child of God can not, will not, ever deny, reject, or walk away from His Lord. There is a definite difference between believing intellectually, and believing with one's heart (Rom. 10:9-10).