Who was the first Muslim to whom the Messenger dictated at his death?

Instructing the dying person (talqin al-muhtadar) is a Prophetic Sunnah. The Prophet, peace and blessings be upon him, did it and commanded it. He instructed his uncle Abu Talib in Mecca despite his polytheism, and he instructed some Muslims in Medina, as in the story of his meeting with a man from Banu Najjar whom he invited to say: "There is no god but Allah."