If we believe "Once saved, always saved", How do you explain Hebrews 6:6?
It’s important to remember the context of Hebrews. The book of Hebrews was written to Jewish people who had supposedly converted to Christianity and were being tempted to desert Christ and return to the religion of their past. They professed faith in Christ; it is questionable how many of them actually possessed faith in Christ. The whole book is a warning against apostasy, the sin of turning one’s back on Jesus Christ and the orthodox faith.
Hebrews Chapter Six warns such people: “It is impossible for those who have once been enlightened, who have tasted the heavenly gift, who have shared in the Holy Spirit, who have tasted the goodness of the word of God and the powers of the coming age, if they fall away, to be brought back to repentance, because to their loss they are crucifying the Son of God all over again and subjecting Him to public disgrace” (vss. 4-6).
Now we know from other Scriptures that a true child of God cannot fall away. Jesus promised that “whoever comes to me I will never drive away” (John 6:37). He assured us that no one can snatch true believers out of the Father’s hand (John 10:28). Nothing can separate Christians from the love of God (Romans 8:39). Therefore, Hebrews 6:4-6 cannot be talking about true believers. Instead, this passage is describing people who profess faith but do not actually possess faith. It is talking about people who (like thousands who attend church services every week!) know a lot about Jesus but never get around to repenting and believing in and following hard after Jesus.
You see, it is possible to be “enlightened,” but not really have the light of Christ fully illumine your dark heart. It is possible to “taste the heavenly gift,” but not really digest and absorb it. It is possible to “share in the Holy Spirit,” but not be regenerated and filled by the Holy Spirit. It is possible to “nibble” at spiritual things, but not really bite down on the gospel and all of its implications. These are sobering truths. They call us to examine ourselves and see if we really are in the faith. If we are, we are secure and cannot lose our salvation. If, on the other hand, we reject the light that we have, it will end up condemning us.
This passage teaches us not to delay putting our faith in Christ alone for salvation. For there will come a time when God will no longer reach out in grace, and repentance will not be possible. “Now is the time of God’s favor, now is the day of salvation” (2 Corinthians 6:2).