Numbers 32:9
For when they went up unto the valley of Eshcol, and saw the land, they discouraged the heart of the children of Israel, that they should not go into the land which the LORD had given them. For when they went up unto the valley of Eshcol, and saw the land, they discouraged the heart of the children of Israel, that they should not go into the land which the LORD had given them.
The spies went up to the valley of Eshcol, saw the land, and by their report discouraged the heart of the children of Israel so that they would not go into the land which the Lord had given them. Moses held up that sin of their fathers from Kadesh-barnea to the children of Gad and Reuben as a warning not to repeat it by refusing to go to war alongside their brethren. That discouraging report sprang from unbelief and cowardice that shrank from conflict at the risk of the Lord's displeasure.
God's promises rest upon the condition of obedience. This discouragement kindled the Lord's anger and brought His oath that none of the men twenty years old and upward who came out of Egypt would see the land sworn to Abraham, Isaac, and Jacob, except Caleb and Joshua because they wholly followed the Lord. The judgment was wandering in the wilderness forty years until the whole generation that had done evil in the sight of the Lord was consumed, and any fresh turning away would leave Israel in the wilderness again and destroy all the people. The rebuke surrounding this history reveals the Lord God as a jealous God who yet bears long with the sins of His people.
The same disobedience, unthankfulness, and unholiness as ancient Israel now hinders God's work, delays the sealing time, and prolongs time. Had God's people walked in His counsel, believed Him, been doers of His word, and kept His commandments, the work would have advanced and the messages of truth would have been carried to all people on the earth, with no need for the angel flying through heaven to cry to the four angels to hold the four winds from blowing on the earth until the servants of God are sealed in their foreheads. Time is prolonged to give the many who have not heard the truth a chance to hear the last message of mercy proclaimed with a loud voice and be converted, so that the great work will go forward.