Numbers 32:11
Surely none of the men that came up out of Egypt, from twenty years old and upward, shall see the land which I sware unto Abraham, unto Isaac, and unto Jacob; because they have not wholly followed me: Surely none of the men that came up out of Egypt, from twenty years old and upward, shall see the land which I sware unto Abraham, unto Isaac, and unto Jacob; because they have not wholly followed me:
None of the men who came up out of Egypt, from twenty years old and upward, would see the land sworn to Abraham, to Isaac, and to Jacob, because they did not wholly follow God. Only Caleb the son of Jephunneh and Joshua the son of Nun were excepted from that oath, because they had wholly followed the Lord. In anger God made Israel wander forty years in the wilderness until all that evil generation was consumed, and the rest fell there for their transgressions and unbelief.
Moses cited the oath to warn Gad and Reuben that refusing to join the war and discouraging Israel from going over repeated the sin of their fathers sent from Kadesh-barnea who discouraged Israel at the valley of Eschol. Turning away would again leave Israel in the wilderness and destroy all the people. The verse shows that God's promises stand upon condition of obedience and are subject to the altering of His purpose when His people disobey.
The verse warns that God's displeasure and judgment fall on those who fail to follow Him faithfully. Professed believers who pursue their own ease and prosperity while avoiding shared burdens and responsibilities, or who persist in selfishness, greed, and deception, will be held accountable, for God sees and searches out hidden sin. As ancient Israel was kept out of the promised land, unbelief, disobedience, unthankfulness, and unholiness now hinder God's work, delay the sealing time, and cause time to be prolonged.
The prolonging is so that many who have not heard the truth may have a chance to hear the last message of mercy proclaimed with a loud voice and be converted. 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 already have been borne to all people dwelling on the face of the whole earth.