Hebrews 3:12
12 Take care, brothers, lest there be in any of you an evil, unbelieving heart, leading you to fall away from the living God.
Hebrews 3:19
19 So we see that they were unable to enter because of unbelief.
In the OT book of Numbers the story of the disbelieving Israelites appears in which the doubt of the Chosen People of God leaves them wandering and dying in the wilderness for forty years. (Numbers 13-14) It is this story that the writer of Hebrews refers to in chapters 3 and 4 of the Book of Hebrews in the NT.
The story is a pretty peculiar one. When the Israelites arrived at the borders of the Promised Land, a land "overflowing with milk and honey," they grew frightened, intimidated by the inhabitants of the land, and refused to enter the land God had given to them. They did this after having been miraculously rescued from Egypt, ten plagues supernaturally afflicting their oppressors, the Red Sea parted before them, a pillar of fire at night and a pillar of cloud by day leading them to the Promised Land. Herded by these incredible, divine events to the land of Canaan, the Israelites nonetheless balked at the prospect of possessing the good land God had given to them. In fact, they began to pine for the slavery of Egypt, grousing at Moses for leading them away from the "leeks and onions" of their bondage! Amazing!
The heart of the problem was that the Israelites simply didn't believe God. In spite of all He'd already done for them, they doubted His promise to them that the land to which He'd brought them was theirs. It was already inhabited, strong people and walled cities occupying the region God said He had given to His Chosen People. The land certainly didn't appear to be theirs. And taking the land from the formidable people already in it felt impossible. And so, going with what they could see and with what they felt, rather than with what God had said, with what He had promised, the Israelites drew back from the Promised Land.
God was, understandably, very angry with His Chosen People (except those who believed), and made them wander in the wilderness for forty years 'til the unbelieving generation of Israelites had died.
What happened at the border of Canaan, the Promised Land, is what happens spiritually every day with God's born-again children. In Christ, they all have come to possess a spiritual "Promised Land," a land of rest, of spiritual plenty, but, going with what they feel and see, they choose instead to doubt what God has said is true of them in Christ, remaining in a spiritual wilderness of moral failure, barred from rich fellowship with God, living in a dry, dusty, hard place as children of God, feeling God is distant and their spiritual life dull and shallow.
All that is required to change this is to begin to believe God, to trust that what He has said is true, regardless of what one may feel or experience. When God, for instance, says, "You are dead unto sin and alive unto me in Jesus" (Romans 6:6-11), the believer may look at their life and think, I'm not dead to sin. Sin fills my life every day. I sure don't feel like I'm dead to sin, either. I think God's got it wrong. This is to do exactly what the Israelites did at the border of Canaan. And, like the Israelites, this doubting God leads to a wilderness of spiritual living. More than this, such doubt is an offense to God, an evil thing that He hates (see above). If there is anyone we should never doubt, it is our holy Maker.
Of course, the problem may not be one of trust, of faith, but of knowledge. Many Christians have no idea of the spiritual Promised Land they've inherited in Christ. They have never heard that they have been co-crucified with Christ and so freed from the power of sin. How, then, can they live by faith in this fact?
Isaiah 5:13
13 Therefore my people go into exile for lack of knowledge; their honored men go hungry, and their multitude is parched with thirst.
Hosea 4:6
6 My people are destroyed for lack of knowledge...
My hope and prayer is that, as you read what I've written here, you will come to know who you are in Jesus and begin, by faith, to enter fully into the spiritual Promised Land you possess in him.
2 Peter 1:3-4
3 His divine power has granted to us all things that pertain to life and godliness, through the knowledge of him who called us to his own glory and excellence,
4 by which he has granted to us his precious and very great promises, so that through them you may become partakers of the divine nature, having escaped from the corruption that is in the world because of sinful desire.
