Fiqh-us-Sunnah Volume 2, Supererogatory Prayer, Fiqh 2.137.

The majority of the people of knowledge are of the opinion that khutbahtul Jumu’ah is obligatory and they support this by the confirmed hadith which state that the Prophet always made the khutbah with the Jumu’ah. In their support they also quote the saying of the Prophet: “Pray as you see me pray,” and the Qur’anic verse: “O you who believe, when the call is proclaimed for salatul jumu’ah, hasten unto the remembrance of Allah.” This verse contains an order to hasten unto the remembrance, which implies it is obligatory, and (the scholars) interpret the remembrance of Allah to include the khutbatul Jumu’ah. AshShaukani refutes the first argument by saying that hadith simply states the action of the Prophet sallallahu alehi wasallam and does not necessarily prove that such an action is obligatory. As to the verse, he regards it as simply a command to be present at the salah which is obligatory and excludes khutbah… Regarding their argument relating to the commandment to “hasten unto the remembrance of Allah,” he says it refers to salah only, which is the real cause for making haste. There is, however, an agreement that the Friday salah is obligatory while there is a dispute over whether or not the khutbah is obligatory. Ash-Shaukani concludes by saying that apparently the correct view is the one held by al-Hassan al-Basri, Dawud az-Zahiri and al-Juwaini, that the khutbah is only a highly recommended act.