(14) باب التَّحِيَّةِ وَالإِمَامُ يَخْطُبُ
Jabir b. 'Abdullah said that the Messenger of Allah (ﷺ) delivered the sermon and said:
When any one of you comes for the Friday (prayer) and the Imam comes out (from his apartment), (even then) should observe two rak'ahs (of prayer).
Reference: Sahih Muslim 875 e
In-book reference: Book 7, Hadith 72
USC-MSA web (English) reference(deprecated numbering scheme): Book 4, Hadith 1901