Yet in this thing ye did not believe the LORD your God,

Wesley's Notes

1:32 Ye did not believe the Lord - So they could not enter in, because of unbelief. It was not any other sin shut them out of Canaan, but their disbelief of that promise, which was typical of gospel grace: to signify that no sin will ruin us but unbelief, which is a sin against the remedy; and therefore without remedy.

Matthew Henry's Concise Commentary

1:19-46 Moses reminds the Israelites of their march from Horeb to Kadesh-barnea, through that great and terrible wilderness. He shows how near they were to a happy settlement in Canaan. It will aggravate the eternal ruin of hypocrites, that they were not far from the kingdom of God. As if it were not enough that they were sure of their God before them, they would send men before them. Never any looked into the Holy Land, but they must own it to be a good land. And was there any cause to distrust this God? An unbelieving heart was at the bottom of all this. All disobedience to God's laws, and distrust of his power and goodness, flow from disbelief of his word, as all true obedience springs from faith. It is profitable for us to divide our past lives into distinct periods; to give thanks to God for the mercies we have received in each, to confess and seek the forgiveness of all the sins we can remember; and thus to renew our acceptance of God's salvation, and our surrender of ourselves to his service. Our own plans seldom avail to good purpose; while courage in the exercise of faith, and in the path of duty, enables the believer to follow the Lord fully, to disregard all that opposes, to triumph over all opposition, and to take firm hold upon the promised blessings.