Why was the funeral prayer performed for the Prophet (peace and blessings be upon him) even though he was forgiven and was a martyr?

Question:
May Allah reward you. Honorable Shaykh, this questioner says: A matter has confused me, which is that no prayer is performed over a martyr; because the prayer is an intercession, and the martyr has been forgiven his sin by his martyrdom. So why did the Companions (may Allah be pleased with them) pray over the Prophet (peace and blessings be upon him), when he had been forgiven ?

Answer:
This Messenger (peace and blessings be upon him) is not described as having died a martyr except on the view that he died because of the poison. This is a martyrdom that does not preclude the funeral prayer, as we said. The one who dies of a stomach ailment, the one who dies of a plague, and the one who is struck by this are martyrs in the Hereafter; they are treated like other funerals. It is specifically the martyr of the battlefield who is the one… Yes. And the Messenger (peace and blessings be upon him) did not die in a battle. If he is a martyr, meaning the specific type of martyrdom, yes.