What does the Bible say about unbelief and its consequences?

Unbelief is presented in Scripture as a grievous sin, chiefly seen in the example of the Israelites in the wilderness who did not enter the Promised Land due to their lack of faith in God's promises. In Hebrews 3:19, it states that their inability to believe resulted in missing the rest God had prepared for them. The sermon highlights that unbelief is the root cause of sin and rebellion against God, making it a serious matter for believers. Those who persist in unbelief face dire consequences, as the Scriptures repeatedly stress that rejecting God's record concerning His Son equates to calling Him a liar. Consequently, the fatal nature of unbelief not only affects present life but seals the eternal fate of the soul.