Sharper than a Two-Edged Sword?

Dane Ortlund comments on a common interpretation of Hebrews 4:12 and its shortcomings. Here's a quote:

I think Hebrews 4:12 is really getting at the same core idea expressed in Jesus' quote of Isaiah 6 in Matthew 13 to the effect that God's revealed truth does not leave people where they were: it either further hardens them or opens their eyes. To some the gospel is the aroma of life, to others the aroma of death (2 Cor. 2:15-17; again the logos of God, v. 17). Which is precisely what is meant in the context of Hebrews 4--the good news of promised rest for God's people landed on some to their hardening and on others to their rejoicing