Deuteronomy 1:35

Surely there shall not one of these men of this evil generation see that good land, which I sware to give unto your fathers,

The oath declares that not one man of the evil adult generation that came out of Egypt and rebelled at the borders of Canaan would see the good land sworn to their fathers, that generation died in the wilderness after forty years of wandering, and the promise of possessing Canaan passed to their children. The exclusion came because of rebellion and disobedience, a refusal to trust God's promise and obey His command despite His leading and care. Distrust and unbelief were their great sin, breaking their solemn pledge and transgressing His holy requirements, with manifest pride, impatience, dissatisfaction and rebelliousness that left them unprepared to enter.

Caleb alone is named as excepted to see the land, because he wholly followed the Lord. Both Caleb and Joshua were exceptions who fully followed the Lord, so only two of the adults who left Egypt entered Canaan. Moses was also barred from entering because of his later failure to trust God and honor Him before Israel at the waters of Meribah; though forgiven when he repented, the consequence was not removed.

God's promises are conditional on obedience, so not one of the good things He promised would fail only upon compliance with the conditions on which the blessings were bestowed, requiring freedom from the sins of the Canaanite nations and a high standard of purity and holiness in loving, fearing and obeying Him. The long delay and wandering in possessing Canaan are not chargeable to God, for He was faithful to His promises, pardoned transgressions and retained Israel as His people, and was more grieved than they that He could not bring them into immediate possession to display His mighty power in deliverance before all nations. Their own perversity made it impossible to manifest His power in protecting them from opposing nations, they did not bear His character of purity, goodness and benevolence and could in no way represent a people whose God is the Lord, and their delay dishonored God and detracted from His glory before surrounding nations, whereas had they yielded in faith to His direction, been governed by His judgments and walked in His ordinances they would long before have been settled in Canaan as a prosperous, holy, happy people.

God is presented here not as a stern, relentless judge but as a loving, compassionate father who would pardon sins upon true repentance and heartfelt sorrow. The words in Deuteronomy 1, including this sentence, are the Lord's words to be read in full together with Deuteronomy 7 and 8 for the admonition of those on whom the ends of the world are come. They teach that every question must be settled by whether it is the will of the Lord rather than human opinion or judgment, that His people must not follow His guidance only to the point that agrees with their own judgment and then cling to their own ideas and refuse to be molded. Everything must be viewed in the light of Christ's example as the truth and true light, copying His self-denial and self-sacrifice, living not to please self, learning the word of the Lord and obeying His voice, and meeting His standard of perfection of character by His merits rather than by feeble human standards.