Because eternal life is integral to the gospel's promise, eternal security is an integral blessing of the gospel, and to deny it is to embrace a truncated gospel.
When we ponder God's promise of eternal security for those in Christ, we can go to these common Scriptures and posit these questions of conviction.
And this is the will of him who sent me, that I should lose nothing of all that he has given me, but raise it up on the last day.
1. How perfect is the Father's will?
2. How good is Jesus at his job?
3. Does the word "nothing" mean nothing, or does it mean "some"?
For this is the will of my Father, that everyone who looks on the Son and believes in him should have eternal life, and I will raise him up on the last day.
4. What does "eternal" mean?
5. What does Jesus' promise about the last day mean for "everyone who believes"?
And we know that in all things God works for the good of those who love him, who have been called according to his purpose. For those God foreknew he also predestined to be conformed to the likeness of his Son, that he might be the firstborn among many brothers. And those he predestined, he also called; those he called, he also justified; those he justified, he also glorified.
6. How does "predestined" jibe with insecurity?
7. If God commits to glorify those he justifies, why do we think he won't?
8. Is justification really justification? Does it mean what it says?
1 Corinthians 1:8-9
He will keep you strong to the end, so that you will be blameless on the day of our Lord Jesus Christ. God, who has called you into fellowship with his Son Jesus Christ our Lord, is faithful.
9. How long does God commit to keep us blameless?
10. Is security dependent on our faithfulness or God's? And how faithful is God?
Therefore he is able to save completely those who come to God through him, because he always lives to intercede for them.
11. Does "completely" mean "partly" or "temporarily"?
[H[e has said, "I will never leave you nor forsake you."
I give them eternal life, and they shall never perish; no one can snatch them out of my hand.
12. Does "never" mean "never"?
13. Does "no one" mean "no one"?
And by that will we have been sanctified through the offering of the body of Jesus Christ once for all.
14. How long does Christ's sacrifice last?
15. How much does Christ's sacrifice cover?
… in hope of eternal life, which God, who never lies, promised before the ages began
16. What kind of life did God promise?
17. When did he promise it?
18. Are God's promises reliable?
19. Wouldn't denying his promise of eternal life be tantamount to calling him a liar?
20. Is your sin more powerful than Christ's blood? Is your weakness more powerful than God's might? Are you the nut he can't crack?
If our religion be of our own getting or making, it will perish; and the sooner it goes, the better; but if our religion is a matter of God's giving, we know that He shall never take back what He gives, and that, if He has commenced to work in us by His grace, He will never leave it unfinished.