Rashi on TanakhDeuteronomy 27

Keep all of the commandment. This denotes constancy. Gardant in Old French.

Erect. In the Yardein. Afterward, remove others from there, and construct an altar with them on Mount Eival. Consequently, we may state that there were three kinds of stones; twelve in the Yardein, a similar number at Gilgal, the same at Mount Eival, as stated in Tractate Sotah.

Explained properly. In seventy languages.

Take heed. As Targum [Onkelos] renders.

This day you have become a people. Each day let it appear to you as if, on that very day, you had entered the covenant with Him.

To bless the people. As stated in tractate Sotah. Six tribes ascended the summit of Mount Gerizim, and six the summit of Mount Eival, with the kohanim and Levi’im and the ark below, at the center. The Levi’im directed their faces toward Mount Gerizim, and began the blessing: ‘Blessed is the man who does not make a sculpture or molten idol, etc.’ These, and the others as well, answered, Amein. They turned, directed their faces toward Mount Eival, and began the curse, saying: ‘Cursed is the man who makes a sculpture, etc.’ [These, and the others as well, answered Amein. They turned, directed their faces toward Mount Gerizim, and said: ‘Blessed is the one who does not revile his father or mother,’ etc. Then they turned, directed their faces toward Mount Eival, saying: ‘Cursed is the one who reviles his father or mother.’] Similarly with all of them, until ‘Cursed is whoever does not uphold.’

Whoever reviles his father. To denigrate. This means the same as “Your brother shall be denigrated.”[25:3]

Whoever casts aside the boundary. Who casts it back, and steals the property. This means the same as “Has been cast back.”

Whoever misleads the blind. Blind concerning a particular matter, and he offers ill advice.

Whoever strikes his fellow in secret. This refers to slander. I have seen [this] in R’ Moshe Hadarshan’s commentary: There are eleven curses here, corresponding to eleven tribes. However, corresponding to Shimon, no curse is recorded. Because he (Moshe) did not intend to bless him before his death, as he blessed the other tribes, he, therefore, did not want to curse him.

Whoever does not uphold. Here, he encompasses all of the Torah in its entirety, which they accepted by an imprecation and an oath.