The Prophet ﷺ used to deliver the Friday sermon standing, then he would sit, then stand again and continue the sermon.
عن النبي ﷺ أنه كان يخطب يوم الجمعة قائما، ثم يقعد، ثم يقوم فيخطب.
Ahmad (2322), Bazzar in Kashf Astar (640), Abu Yaala (2490), and Tabarani in Al-Kabir (12090) all narrated it through the route of Hajjaj, from Hakam, from Miqsam, from Ibn Abbas, who mentioned it. Hajjaj here is Ibn Artah, a mudallis, and he narrated it using ambiguous transmission wording, but it has been narrated paired with Ibn Abu Layla.Abu Yaala (2620) narrated it from Bishr bin Walid, who said, Abu Yusuf (that is, Yaqub bin Ibrahim, the judge and companion of Abu Hanifa) informed us, from Ibn Abu Layla and Hajjaj bin Artah, from Hakam, from Miqsam, from Ibn Abbas, who mentioned it. Ibn Abu Layla added a phrase, saying, "So he sat down briefly."Ibn Abu Layla here is Muhammad bin Abdul-Rahman bin Abu Layla, who had weak memory but was not a mudallis, and their shared teacher, Hakam bin Utayba, is reliable. With this corroboration, the hadith rises to the level of hasan.