"Take heed, brethren, lest there be in any of you an evil heart of unbelief, in departing from the living God." Hebrews 3:12
When the Lord gives us a warning in His word, it would definitely do us good to pay attention to what He is saying. His warnings are always for our benefit. Above is one of those warning. What is the warning? The warning is- in a nutshell- "guard your heart". Be careful not to allow it to become unbelieving.
He uses the example of Israel here to teach us what He means. In verse ten He tells us that they were always going astray from Him in their hearts. The heart is the "heart of the matter". The Bible tells us that God is after our hearts. It tells us that with our hearts we believe unto salvation. The greatest commandment is that we love the Lord with all our heart.
They didn't guard their hearts. They allowed unbelief to come in even after they had seen all the miracles that He had done for them. They tempted Him to do more after He had already given them everything they needed- their hearts were full of discontent. When He tried to take them into the promised land, they did not believe that He was able to do it. They believed what they saw instead of what He said. They also wanted God to fulfill their every desire and follow their plans- when, where and how they wanted things to go.
Are you following in their footsteps? Are you listening to the accusations of the enemy against God? Are you tempting Him? Are you listening to the negative reports when He has already given you His word on the matter? Are you dissatisfied with what God is doing? Are you trying to make Him conform to your plans and do things your way? Then beware and on guard, you are on your way to having a "straying heart" and a straying heart strays away from God. And when it strays away from God there are consequences. (Just ask those Israelites who did not enter into the promised land.) Or are you guarding your heart from unbelief?
How do we keep from departing/straying from the Lord? How do we keep from having an evil heart of unbelief? By guarding our heart. We do that by keeping it clean and pure before Him. That is done through faith. Believe what He says. Cleave to Him no matter what. Trust Him no matter what the situation looks like. Follow Him and allow Him to do the leading. Renew your mind with His word. Hide His word in your heart. Refuse to listen to the accusations of the enemy. Be content where you are at the moment but keep seeking Him. Let His word establish peace in your heart. Be led by the Spirit and not your own flesh or selfish desires. Remember, the just live by faith, not by sight... and not by our wants and desires.
Have a great day. Guard your heart from unbelief so that you don't depart from the Lord.
For further reading:
Psalm 51:10; 119:11
Hebrews 3:1-2; 13:5
2 Corinthians 5:7