The Book of Hebrews tells us, “For the word of God is living and active, sharper than any two-edged sword, piercing to the division of soul and of spirit, of joints and of marrow, and discerning the thoughts and intentions of the heart. And no creature is hidden from his sight, but all are naked and exposed to the eyes of him to whom we must give account.” (4:12-13)
The two-edged sword is judicial. The sword according to Jamison, Fausset and Brown Commentary means “the Word of God, the sword of the Spirit with double edge, one edge for convicting and converting some, (Hebrews 4:2) and the other for condemning and destroying the unbelieving” (Hebrews 4:13-14). The text also tells us this sword, The Word of God, is “piercing to the division of soul and of spirit, of joints and of marrow, and discerning the thoughts and intentions of the heart.” That’s a deep cut.
I think this verse is first of all trying to tell us to individually use the sword on ourselves to cut the unbelief from the belief out of our own hearts. To cut into our deeper self to excise all improper thoughts, motives and conflicts. The sword is for personal use. The double edge is not for chopping away at other believers or unbelievers… it is to chop away at our own issues.
“The one who rejects me and does not receive my words has a judge; the word that I have spoken will judge him on the last day.” Jesus