Charles Spurgeon Commentary Deuteronomy 29:5-6

"And I have led you forty years in the wilderness: your clothes are not waxed old upon you, and thy shoe is not waxed old upon thy foot. Ye have not eaten bread, neither have ye drunk wine or strong drink; that ye may know that I am Jehovah your God." — Deuteronomy 29:5-6 (ASV)

Either there had been means of frequent renewal of their garments, or else by a miracle these garments had never worn out; and the very shoes that they put on their feet on the Passover night were still on their feet. If not the same, they were still shod, though they trod the weary wilderness, which could well have worn them out until they were bare. You have not eaten bread, neither have you drunk wine or strong drink: – a nation of total abstainers for forty years.

There was no bread in the wilderness for them, and there was no wine. It may have been obtained as a great luxury, as it probably was, for we have reason to believe that Nadab and Abihu were slain by fire before the Lord because they were drunk when they offered strange fire; but considering the people as a whole, anything like wine had not crossed their lips for forty years, yet there they were, strong and healthy. That you may know that I am Jehovah your God.