A couple days ago I ranted on about complete redemption. That's been on my mind a lot recently, largely as a result of my reading.
One thought that's been particularly striking has been to consider redemption from God's point of view. From a self-centered perspective, we can imagine being uncertain of redemption; but when we consider this from God's perspective, we realize this is foolishness. When we look from God's perspective, we recognize the main point is not whether a sinner is redeemed, but whether Christ's sacrifice is accepted. If a true believer were to lose his salvation, it would imply that God had rejected not the believer, but Christ Himself.
When we say it this way, we can see what a wicked idea this is.
But this is fundamentally the teaching of the Epistles, and Hebrews in particular. The repeated assertion of Hebrews is that Christ is sitting at God's right hand, because His sacrifice has been accepted: "when he had by himself purged our sins, sat down on the right hand of the Majesty on high" (Hebrews 1:3). It is as having offered one sacrifice for sins that He sat down (Hebrews 10:1--14). Christ's acceptance to God's right hand is proof that His sacrifice has been accepted. Further, it's presented as proof that the sacrifice was once-for-all. There can never be need of another.
Because there can never be another sacrifice for sins, the idea that a believer can become unsaved has grave implications. If God is to reject Christ's sacrifice because I sinned, then there's no sacrifice for anyone else. There's only one sacrifice for sins: there's not one for me and one for you. That's the whole point of Hebrews 9 & 10. So here's the problem: if we're all redeemed by the one-and-only-one offering of Christ, then not one of us can be lost unless we're all lost. If God were to reject me, He must also reject every other person who's been redeemed by Christ. If God were to reject me, He'd be bound to kick Paul out of Heaven too; because there's only one sacrifice for sins.
I mentioned last time that a missionary once told me they didn't like to teach eternal security on the mission field, because it might give people license to sin. Leaving aside how heartless that is--- that someone would actually think it's a good idea deliberately to rob a true believer of assurance--- let's consider for a moment how wicked that is. This person apparently thought it was a good idea to blaspheme by casting aspersion on Christ. This person denied Christ because he thought he couldn't trust another believer.
There is no greater wickedness than blasphemy. It would be far better for every believer to fall into all kinds of sin, vice, and corruption than for one person to blaspheme by casting aspersion on God's Son. What this missionary did was far, far worse than what he was afraid the poor people around him might do. It's like chopping off a finger for fear of a hangnail.
This is ultimately what Hebrews teaches us. Redemption's not about us, it's about Christ. The real point of His redeeming us is not that we've gotten boundless blessings, but that God is pleased with His Son.