"The brainwashing of the Palestinian society by the PA and others leads to evil violence," Emmanuel Nahshon wrote. "My heart goes to Yotam's family. May his memory be a blessing."
The attacker, who is believed to be about 16 or 17, had called for an uprising in a long Facebook post.
The Israeli army said the attacker was shot and killed by a civilian who was passing by.
It said troops would be sent to the Kubar village nearby, where the teenage attacker is believed to have lived.
The IDF said on Twitter: "The terrorist infiltrated the community of Adam, north of Jerusalem, and stabbed three civilians. Troops arrived at the scene and are searching the area."
Hamas has said that the attack was an act of heroism and revenge for the three fighters killed in Gaza on Wednesday.
