BEWARE! Hebrews 3:12 Unbelief is a stubborn refusal to trust God’s word. It is like saying, “I am not sure it is true, therefore I won’t believe it.” It is the most serious of sins, not just because it leads us away from God, but because it charges God with not being truthful, making Him out to be a liar. An “evil heart of unbelief” chooses not to trust in God’s word and His promises, and decides to disobey God’s voice. That cuts a person off from God.
Judgment comes on those who refuse to believe in the “only true God, and Jesus Christ,” who He sent into the world to save us from the wrath to come. Christ is the Truth; He is God’s final Word. He was made flesh and dwelt among us. To turn away from Him is to turn away completely from God.
When we hear God's voice, we must respond to Him from our hearts. Our naturally hard hearts are softened when we hear God’s voice through His word and allow it to work in us, as the Holy Spirit makes His truth come alive. Then, we will turn from being lukewarm in heart to hearts full of gratitude and love for Him. Pride, arrogance, self-seeking, and restlessness change us into people who live holy, righteous, and godly lives that are soft and honest before God.
Sin starts in the heart. Error first occurs in the heart. Unbelief hardens the heart, leading to sin and sorrow. Unbelief then causes a separation from the living God, replacing the faith that connects us to God's strength and fullness with emptiness and weakness. Some people change their opinions about God. Others test God with their complaints, murmuring, and disobedience.
The Holy Spirit, through the writer, warns the Hebrew believers and us to take heed, lest we allow unbelief to take from us all that we have in Christ that enables us to live effective lives for Him. A lost life of a believer leaves us empty, powerless over sin, and without joy, even though we are saved by God’s grace. He also warns those who are simply Jewish “brethren" that they will be eternally lost if they turn away from the living God.
In our relationship with God, everything depends on the condition of our hearts. It is with the heart that man believes and is saved. Faith is the first spiritual function of a believing heart, showing by its fruits that we love God and have found our life in God. Now we know God, communicate with God, trust God’s word, obey God’s voice, walk in His light, and enjoy the life He gives by faith.
The terrible evil of unbelief makes fellowship with God impossible. The “living God” hears our prayers, teaches us through His word, and guides us by the Holy Spirit of God, but unbelief cancels out all of these blessings. We must take heed, pay attention to, and not allow anything to let unbelief take hold in our hearts and minds. Our lives, our faith, and our joy depend on what we allow into our hearts. Our spiritual strength and fruitfulness, our closeness to God, and our experience of Him working in us depend on the state of our hearts. Our faith must be in the living God.
The living God is the Living Father, Son, and Holy Spirit who knows every thought we have, every attitude we display, and every action we take. This “falling away” is from Him, a Person, not falling into sin. Neglecting God results from an evil heart of unbelief. When we become hardened against Him, we are not victims. No one forces us to do this, nor does it come from forces outside of us.
Unbelief develops gradually, day by day, as we “fall away” from God through our self-centered lifestyles and careless indifference toward Him. This isn’t just about missing church services or doctrinal teachings, but about turning away from a reality, a Person—the Living God. He is the Mighty God, the Judge of all things and every person. Our Lord is the Mediator between God and man; He is our Intercessor. Someone may have received eternal life, but neglecting God and taking Him for granted is a serious warning. We will face Him who chose us to live for Him and be with Him. Do not neglect Him or assume life will be better without Him; that is a grave mistake with lasting consequences.