Deuteronomy 29:21

21 And the Lord shall separate that man for evil of all the children of Israel, according to all the curses of the covenant that are written in the book of this law.

Deuteronomy 29:21 Meaning and Commentary

Deuteronomy 29:21

And the Lord shall separate him unto evil out of all the
tribes of Israel
Unto the evil of punishment, devote and consign him to it, and make him a visible and distinguished mark of his displeasure and vengeance. So some men are righteously separated from others, and preordained unto condemnation, being wicked and ungodly men; for such God has made or appointed for the day of evil; see ( Proverbs 16:4 ) ( Jude 1:4 ) ;

according to all the curses of the covenant that are written in this
book of the law;
the evil of punishment he shall be separated unto shall be according to them, or include them all; the sense is, that the wrath of God, and the whole curse of the law due to him for his sin, shall come upon him; see ( Deuteronomy 28:16-18 )

Deuteronomy 29:21 In-Context

19 And it shall be if one shall hear the words of this curse, and shall flatter himself in his heart, saying, Let good happen to me, for I will walk in the error of my heart, lest the sinner destroy the guiltless with :
20 God shall by no means be willing to pardon him, but then the wrath of the Lord and his jealousy shall flame out against that man; and all the curses of this covenant shall attach themselves to him, which are written in this book, and the Lord shall blot out his name from under heaven.
21 And the Lord shall separate that man for evil of all the children of Israel, according to all the curses of the covenant that are written in the book of this law.
22 And another generation shall say—even your sons who shall rise up after you, and the stranger who shall come from a land afar off, and shall see the plagues of that land and their diseases, which the Lord has sent upon it,
23 brimstone and burning salt, (the whole land shall not be sown, neither shall any green thing spring, nor rise upon it, as Sodom and Gomorrha were overthrown, Adama and Seboim, which the Lord overthrew in his wrath and anger:)—

The Brenton translation of the Septuagint is in the public domain.