"11 Let us therefore strive to enter that rest, so that no one may fall by the same sort of disobedience. 12 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. 13 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."
Hebrews 4:11-13
Since it is by faith that we enter into God's rest and salvation, the enemy is unbelief (11), and this is just as true today as it was in the days of the Israelites. Their long history of failure in this respect is held up to us as a grim warning and as something against which we must at any cost arm ourselves. 'Let us labour', says the Apostle. There is, it would seem, a play upon words and a paradox here, for the 'work' of faith to which the gospel summons us is to cease from works, and 'ceasing from works' is the hardest thing on earth to do, when we are proud of our works and are depending on them for our acceptance with God. A drowning man may find it extremely difficult to stop struggling when a would-be rescuer bids him to, but his safety will certainly depend on his doing so. He must cease his own efforts to save himself and commit himself to the 'works' and ‘efforts' of another. But this is in fact to cease from himself, to 'die' to his natural inclinations altogether. This is the inner meaning of repentance, and explains why so many 'good-workers' are unwilling to humble themselves to receive the gift of salvation from Christ. It is a proud independence of spirit that keeps them back. And it is this that the Word of God, quick and powerful as it is (12), searches out and exposes in a man's heart, discerning his thoughts and intents and revealing the bitter root of unbelief within him.