Maybe so, but that's not what Hebrews 4:12 means, despite the number of times we've all heard someone refer to the Bible as 'living and active, sharper than any two-edged sword, piercing to the division of soul and of spirit,' and so on.
The 'word' of God in Hebrews 4:12 is logos, a flexible Greek word which does at times (not often) refer to written Scripture (e.g., 2 Tim. 2:15?).
But if we are sensitive to the context we notice that logos has already been used a bit earlier, in Hebrews 4:2--'For good news came to us [lit. 'we have been good-news'ed] just as to them, but the message [logos] they heard did not benefit them . . .' The ESV rightly interprets logos here as something spoken (not something written), a 'message,' in accord with its connection with the verb euangelizomai, 'to speak the gospel/good news,' which occurs again in Heb. 4:6.
The word of God that is living and active and all the rest is the gospel. This is not mutually exclusive with written Scripture, of course. The two, gospel and Bible, overlap in all kinds of ways. But they are distinct, and one is being denoted in Hebrews 4 and the other is not.
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.
The gospel, joyfully heralded in all its truth and starkness, is a piercing message that penetrates as no other message does or can, either reinforcing our natural recalcitrance or igniting fresh freedom. The gospel is the truest, most incisive diagnostic, a spiritual x-ray, a light shining way down deep into the darkest recesses of the heart. Hearing it either further enslaves or further liberates. It does not leave us as we were.