Therefore let us leave the elementary doctrine of Christ and go on to maturity, not laying again a foundation of repentance from dead works and of faith toward God, and of instruction about washings, the laying on of hands, the resurrection of the dead, and eternal judgment.Bobby Jamieson deftly exposes the flawed exegesis at the root of that argument in this post at the 9Marks blog. Here's his conclusion:
So, when the author of Hebrews “moves on from the gospel,” what does he move on to? The priesthood of Christ, the sacrifice of Christ, the heavenly intercession of Christ, the new covenant mediated by Christ, the future return of Christ, and how all of that enables us to turn from dead works and serve the living God.His follow-up post spells out some warnings and advice for those of us who believe that the gospel remains at the epicenter of Christian life and discipleship.
In other words, the author of Hebrews doesn’t move on from the gospel; he moves deeper into the gospel. He doesn’t leave the gospel behind, but instead claws his way into more and more of its riches.
So then, at least for the author of Hebrews, leaving behind elementary teachings doesn’t mean leaving behind the gospel. Instead, it means diving into the deep end instead of splashing around in the shallows.