In Hebrews 3:7, the author says that the Israelites failed to enter the rest across the Jordan because they had “hard hearts.” It seems that the Bible uses the idea of a hard heart when it refers to those who reject God’s Word for whatever reason. The Israelites referred to in Psalm 95 as quoted by the author of Hebrews failed to believe God’s promise of rest beyond the Jordan because of fear of those who already occupied the land. They truly liked what they saw regarding the land itself. Their report included the fact that the grapes and fruits were better than anything they had ever seen. But to them it was too good to be true. Coming from a history of around 400 years of slavery, they could not believe that God intended such a wonderful thing for them and that it was theirs simply for the taking. They wouldn’t believe that because their hearts were hard.
Jesus frequently called those who rejected His wonderful message of saving grace apart from the confines of the law hardhearted. He wants to save them and us from slavery under a system that we could never live up to and from which we could never be free on our own. All of us, under the law, are sin-sick and cannot help ourselves. Jesus said, “For this people’s heart has become calloused; they hardly hear with their ears, and they have closed their eyes. Otherwise they might see with their eyes, hear with their ears, understand with their hearts and turn, and I would heal them” (Matthew 13:15). Even believers sometimes fall into the trap of unbelief because Jesus’ message is just too good to be true. Even Jesus’ disciples had trouble with this. “Afterward he appeared to the eleven themselves as they were reclining at table, and he rebuked them for their unbelief and hardness of heart, because they had not believed those who saw him after he had risen” (Mark 16:14).
What’s too good to be true? What’s so hard to believe? Righteousness is ours apart from the law. Jesus fulfilled the demands of the law on our behalf. The only righteousness available to us today is free! It’s the gift of God through faith in Jesus Christ. That’s too good to be true. Jesus declared that the Old Testament was about Himself and that Moses testified to this truth. But legalists cannot hear that. The Amplified Bible translates 2 Corinthians 3:14 this way, “In fact, their minds were grown hard and calloused [they had become dull and had lost the power of understanding]; for until this present day, when the Old Testament (the old covenant) is being read, that same veil still lies [on their hearts], not being lifted [to reveal] that in Christ it is made void and done away.” When we focus on what we do, rather than on what Christ did for us we will lose out on God’s rest. Paul says in Galatians 2:21 “if righteousness were through the law, then Christ died for no purpose.”