1)
Which peg will cease?
1.
Rashi: The grandeur of Shevna. Radak - he thought that his honor will last until he dies - "Chotzevi Marom Kivro" (16). Malbim - first the peg will be displaced. Afterwards, it will be chopped, via Shevna being taken in fetters.
2)
Which burden will be cast off?
1.
Rashi #1: His family and entourage that depended on him, and attributed their glory to him. Because he was compared to a peg, it compared those who glorify themselves in him and depend on him to a load hanging from a peg. Radak - when the peg breaks, everything that hung from it falls.
2.
Rashi #2: The Masa (Nevu'ah) about him will be fulfilled.
