Hebrews 4:12 "For the word of God is living and active and shaper then any two-edged sword and piercing as far as the division of soul and spirit, of both joints and marrow, and able to judge the thoughts and intentions of the heart."
The Word of God has double power that is indicated by the words 'two-edged sword. The Word cuts deep into the thoughts and intentions of the heart. It judges all that is in the heart, judging unbelievers as well as searching the hearts of believers. It goes to the very depths of a person, revealing what is hidden and bring it into the light. God knows all things, he searches all hearts. (1 Chronicles 28:9)
Do you stand firm in the faith and believe the Bible is God's Word ? God Breathed ? Unless you believe the Bible is the very word of God, it will have no authority or effect. Jesus came and made the scriptures alive and real to people. Jesus came and made the scriptures alive, and they believed ! Faith and Grace working together produced reverence and worship to God. The old testament Scriptures were not just words in a book, but they were the Living word of God made flesh in Jesus Christ. John 1:1) His disciples preached the Gospel Jesus came to bring, and lives were changed because of that Truth. 1 Thess 2:13 testifies to this fact:
"For this reason we also constantly thank God that when you received the word of God which you heard from us, you accepted it not as the word of men, but for what it really is, the word of God, which also performs it's work in you who believe."
Reading Hebrews 4:12 gives us godly wisdom, and gives great reverence of God's all-knowing, he knows us better then we know ourselves. It is a forwarning and gives us the opportunity to repent of sin and be right with God. We must be firm in the faith and believe Him.
In Matthew Henry's commentary it says this about the power of God's word: " It is a discerner of the thoughts and intents of the heart. The word will turn the inside of a sinner out, and let him see all that is in his heart. The perfections of the Lord Jesus Christ. His person, particularly His omniscience, none of the creatures can be concealed from Christ; and there are none of the motions and workings of our heads and hearts but what are open and manifest to Him. This omniscience of Christ should engage us to perserve in faith and obedience.
Omniscience means: A divine attribute of God; God's knowing of all things of proper knowledge. The divine attribute of perfect knowledge. This is declared in numberous scriptures. The perfect knowledge of God is exclusively His attribute. It includes all things that are actural and all things that are possible.
Jesus says in - John 12:48 "He who rejects Me and does not recieve My sayings, has one who judges him; that word I spoke is what will judge him at the last day."