Deuteronomy 1:41
Then ye answered and said unto me, We have sinned against the LORD, we will go up and fight, according to all that the LORD our God commanded us. And when ye had girded on every man his weapons of war, ye were ready to go up into the hill.
The words were spoken after a night of lamentation and sleepless despondency over the forty-year sentence to wander in the wilderness, when Israel resolved to redeem its cowardice by refusing the wilderness and seizing Canaan in hope that God would accept its work and change His purpose. It was a false confession and a second rebellion, answering condemnation with a resolve to go up and fight and take the land by their own might. The sorrow was utter despondency turning after that sleepless night into a hope to undo cowardice by grasping the promise on their own terms.
The admission of sin against the Lord acknowledged that sin and unbelief had shut them out, which vindicated the justice of the sentence, but the hearts were unchanged and the sorrow was for the judgment rather than true and sincere repentance that could have brought another trial. The profession to act just as God had commanded was blinded by transgression and untrue, because the Lord had never at that time told them to go up and fight; transgression had turned light into darkness so they could not see this. What God had once made their privilege and duty at His appointed time had been withdrawn through willful neglect, and His purpose was not for them to gain the land then by warfare but by strict obedience and submission and unqualified obedience.
Having distrusted God's power to work with them when He bade them go up, they now presumed on their own strength to do the work independent of divine aid, doing in the face of divine prohibition at Satan's urging what they had refused when God required it. The verse exposes human nature in rebellion against the will of God, in that the same men who had complained about risking warfare were now rashly determined to carry out their own will at all hazards, as though weak humanity could overthrow the purposes of Jehovah. Though girded and ready in their own estimation, they were sadly deficient before God, marching as a tumultuous disorganized company contrary to the command of God and the solemn prohibition of their leaders, without Moses the appointed leader, without the cloudy pillar as the symbol of the divine presence and the leading of the Son of God, and without the ark.
Because of that absence of God the presumptuous attack in direct opposition to the command of God ended in defeat and rout, with thousands slain. The later resolve to fight did not reverse the consequences or undo the earlier disobedience, so the adults who had left Egypt were still refused entry into the promised land because they had rebelled and had not obeyed and wholly followed Him. The verse therefore teaches that admitting sin and professing willingness to obey are not enough when people then act against God's command, and its failure stands as a warning that God's promises are conditional on obedience.
By contrast, going forward in obedience with Moses present to strengthen hearts with hope and faith, with the Son of God enshrined in the cloudy pillar leading the way, and with the sacred ark accompanying the host, brings God's signal working for His people. The lesson is that the mighty God of Israel can be trusted and will work if His requirements are obeyed, so everyone seeking to follow duty must go forward at any cost despite doubt and unbelief and obstacles that appear insurmountable and fill the soul with dread, humbly trusting in God, and formidable difficulties will vanish in the path of obedience. The surrounding chapter is to be read whole as the word of the Lord for admonition to those upon whom the ends of the world are come, calling for following the Lord's guidance fully rather than only up to the point that agrees with one's own judgment, for giving up one's own ideas and opinions to be molded after the Lord's likeness, and for viewing everything in the light of Christ's example and perfection of character rather than by feeble human standards.