Rashi: So Nasan ha'Navi said about Shlomo "v'Hochachtiv b'Shevet Anashim" (Shmuel II, 7:14) - this is Rezon ben Elida, whom Hashem sent to oppose him (Melachim I, 11:23). Radak - one strikes his son with a staff in a way that will not kill him - "Ki Sakenu va'Shevet Lo Yamus", "v'El Hamiso Al Tisa Nafshecha" (Mishlei 23:13, 19:18). Hashem will strike [a king from David who sins] with plagues, illnesses and a staff. He will hand him over to his enemies; He will not remove kingship from him.

Malbim: If the sin is Pesha (rebellion), which has no source in the Nefesh, only in the body, which rebels, Hashem strikes with a staff, which is external to the body. Also refer to 89:33:2:3.

Rashi: This is like Nasan said "v'Hochachtiv