“Take heed, brethren, lest there be in any of you an evil heart of unbelief, in departing from the living God. But exhort one another daily, while it is called To day; lest any of you be hardened through the deceitfulness of sin. For we are made partakers of Christ, if we hold the beginning of our confidence stedfast unto the end; While it is said, To day if ye will hear his voice, harden not your hearts, as in the provocation. For some, when they had heard, did provoke: howbeit not all that came out of Egypt by Moses. But with whom was he grieved forty years? was it not with them that had sinned, whose carcases fell in the wilderness? And to whom sware he that they should not enter into his rest, but to them that believed not? So we see that they could not enter in because of unbelief.” Hebrews 3:12-19 KJV.
So what is the cure for unbelief? Faith. Faith is the opposite of doubt or unbelief. Unbelief in what? Unbelief in the promises of God. The children of Israel had been given a promise by God that He would give them the land of Canaan and help them to possess it, if they would follow His lead. Caleb and Joshua told the children of Israel that they were well able to enter the Promised Land, that God would open the way for them and give it to them. But the 10 other unfaithful spies lied to the children of Israel about this, saying many discouraging things to them, so that they did not believe the promise of the Lord.