"Wherefore (as the Holy Ghost saith, To day if ye will hear his voice, Harden not your hearts, as in the provocation, in the day of temptation in the wilderness: When your fathers tempted me, proved me, and saw my works forty years. Wherefore I was grieved with that generation, and said, They do alway err in their heart; and they have not known my ways. So I sware in my wrath, They shall not enter into my rest.)"
There are many, very many, who, while professing faith in Christ, yet perish in unbelief. In these verses, the Spirit of God identifies unbelief as the greatest of all evils and gives us a strong warning against it by example (Ps. 95:7-11).
The Israelites professed to be and were called God's people, but they were a rebellious, murmuring, unbelieving people. "Now all these things happened unto them for ensamples: and they are written for our admonition, upon whom the ends of the world are come" (1 Cor. 10:11). Four things are here stated about the unbelieving Jews who perished in the wilderness under the wrath of God. Let us lay them to heart and be warned.
1. Those who perished, perished because they would not hear God's voice as he spoke to them by Moses. God speaks to us by his Son. He declares, "This is my beloved Son, hear ye him" (Heb 1:1-2). God has given us greater light than he gave the Jews. If we perish, as they did, in unbelief, ours will be the greater condemnation.
2. Those men and women perished because they hardened their hearts. There is a natural hardness of heart with which we are all born; but this text speaks of a willful, deliberate, voluntary hardness of heart, a hardness of heart that is acquired by the rejection of truth, despising the light of the gospel and the warnings of Holy Scripture, by a willful continuance in rebellion and unbelief (Matt. 11:20-24; Pro. 29:1).
3. Those who perished in the wilderness perished because they dared to defy God. They tried his patience, despised his and long-suffering, and murmured against his providence. Though they had seen his goodness, lived upon his provisions, enjoyed his protection, and witnessed his miracles for forty years, still, they believed him not.
4. God was grieved with that nation. They wearied him with their sins, displeased him with their unbelief, and provoked him to anger with their complaints. He therefore declared that they could not enter into the land of Canaan, the promised land of rest. So, too, all who harden their hearts against the gospel of God's free and sovereign grace in Christ shall be forever shut out of heaven by their unbelief.