They shall be upon you: that is, they will befall you, come down on you.

A sign and a wonder: see the two words in 4.34. Here they mean a solemn warning, a powerful reminder, to other people, as Good News Translation makes clear. Some, however, take this to be a solemn warning to the Israelites themselves; but the Hebrew preposition translated upon seems to require the other meaning. New Jewish Publication Society’s Tanakh has “They shall serve as signs and proofs against you and your offspring…”; or we may say “… that God is punishing you.”

You and your descendants for ever: formally this contradicts the passages that foretell the total destruction of the Israelites.

Quoted with permission from Bratcher, Robert G. and Hatton, Howard A. A Handbook on Deuteronomy. (UBS Helps for Translators). New York: UBS, 2000. For this and other handbooks for translators see here .