The passage
      v12. The writer to the Hebrews describes the word of God for us. This word was proclaimed to the rebels in the wilderness and is the same word that is proclaimed to us in our day. This "word of God" is the communicated will of God for his people.
        i] It is living, Act.7:38, 1Pet.1:23. It is a personified word from God. A personal communication possessing the substance of the Divine. In that sense it is unlike human communication which contains mere words without substance.
        ii] It is active, Isa.55:11. It is a communication which fulfills the purpose for which it is uttered.
        iii] It is incisive, penetrating. It is not just sharp, but sharper than the sharpest doubled edged sword. In that sense the word of God can cut either way - in judgement or blessing. So, the Word of God can probe the innermost motives of the real self and bring them out into the open, and then, with the self exposed to the light, prompt repentance and forgiveness. "He will bring to light what is hidden in darkness and will expose the motive of men's hearts", 1Cor.4:5.
      v13. The writer concludes by pointing out that we might be able to conceal our rebellion from our neighbors, even from ourselves, but not from God. Before the living God, all creatures are exposed in his sight. So, before the living God our rebellion is exposed and made powerless ("laid bare", as a wrestler grabs an opponent by the neck and renders them powerless). In this exposed state we need to remember that our final reckoning must be made before God, the one "to whom our account must finally be rendered", and that being the case, we definitely need a merciful High Priest to see us safely through.

A path to travel
      Much of the New Testament focuses on the danger of a lost faith and yet, we don't seem to recognize the problem. We tend to see ourselves as secure in our Christianity, while at the same time view non believers as the ones in danger of judgement. For this reason, much of our gospel preaching tends to be focused on the rebellion/sin of the world. Not that the unbeliever isn't a slave to sin and isn't facing judgment, it's just that we often forget about our own rebellion and judgment, a judgment that begins with the household of God. The Bible constantly speaks of unbelief, yet not so much to those who are lost, but rather to those who "share in Christ."
      The writer to the Hebrews in 3:7-4:11, reminds us that the people of Israel heard the voice of God. They had a living and powerful word from God. That word was actualized in fire, cloud, water from the rock, manna...... and at Mount Sinai in signs, wonders and speech. Yet, they "hardened their hearts", they nurtured a "sinful unbelieving heart that turns away from the living God". "The message they heard was of no value to them, because those who heard did not combine it with faith." The living word of God had the power to take them into his "rest", into the promised land, into the blessings of God, (eternal life). "Yet they couldn't enter because of their unbelief."
      Now, says the writer to the Hebrews, "see to it, brothers, that none of you has a sinful, unbelieving heart that turns away from the living God." "Make every effort to enter that rest" (by grace through faith). As Paul writes, "These things happened to them as examples and were written down as warnings for us", 1Cor.10:11. Do we take the warning to heart? If we don't heed the warning then we are in trouble, for the word that has the power to carry us into "God's rest", also has the power to condemn us.
      Having been warned, we are given the solution in 4:14-16. "Let us hold firmly to the faith we profess". In simple terms, let us look to Jesus who has himself faced all the temptations and troubles that we now face. "Let us then approach the throne of grace with confidence, so that we may receive mercy and find grace to help us in our time of need." Hold onto Jesus, he will carry us through.