Zayd ibn Thabit said: The Messenger of Allah, peace and blessings be upon him, ordered me, so I learned the writing of the Jews for him. He said: "By Allah, I do not trust the Jews with my letter." So I learned it, and no more than half a month passed before I had mastered it. I would write to them when he wrote, and I would read to him when something was written to him. (1)

Chapter 3: On Writing Knowledge

3646 - Musaddad and Abu Bakr ibn Abi Shaybah narrated to us, both saying: Yahya narrated to us, from Ubaydullah ibn al-Akhnas, from al-Walid ibn Abdullah ibn Abi Mughith, from Yusuf ibn Mahak, from Abdullah ibn Amr, who said: I used to write down everything I heard from the Messenger of Allah, peace and blessings be upon him, intending to memorize it. But Quraysh forbade me, saying: "Do you write down everything you hear from the Messenger of Allah, peace and blessings be upon him, while the Messenger of Allah, peace and blessings be upon him, is a human being who speaks in anger and in pleasure?" So I stopped writing. Then I mentioned that to the Messenger of Allah, peace and blessings be upon him, and he said: "Write, for by Him in Whose hand is my soul, nothing comes out of it but truth." (2)

(1) Authentic. This chain is good because of Ibn Abi al-Zinad—whose name is Abd al-Rahman. Abu al-Zinad: he is Abdullah ibn Dhakwan.
It was also recorded by al-Tirmidhi (2912) via the chain of Abd al-Rahman ibn Abi al-Zinad, with this chain. He said: This is a good authentic hadith.
Al-Bukhari attached it (7195) in a definitive form. It is in the "Musnad" of Ahmad (21618).
It was also recorded by Ahmad (21587), al-Tahawi in "Sharh Mushkil al-Athar" (2038), and Ibn Hibban (7136) via the chain of al-A'mash, from Thabit ibn Ubayd, from Zayd ibn Thabit, who said: The Messenger of Allah, peace and blessings be upon him, said to me: "Do you know Syriac? Letters come to me." He said: I said: No. He said: "Then learn it." So I learned it in seven days. This chain is authentic. Al-Bukhari explicitly stated in his "al-Tarikh al-Kabir" that Thabit ibn Ubayd heard from his freed slave Zayd ibn Thabit, and he recorded in "al-Adab al-Mufrad" (286) what indicates more than his hearing from Zayd ibn Thabit, contrary to what al-Dhahabi assumed in "Tarikh al-Islam" that his narration from his freed slave was disconnected.
See the complete takhrij of this second chain in "al-Musnad" and "Sahih Ibn Hibban."

(2) Authentic. Its chain includes al-Walid ibn Abdullah ibn Abi Mughith, who is truthful, and the rest of its narrators are reliable. It was also recorded by al-Darimi (510) via the chain of Yahya ibn Sa'id, with this chain. Al-Hakim recorded it in "al-Mustadrak" (358) and said: Its chain is authentic, and they did not exclude it. Al-Dhahabi agreed with him. It is in the "Musnad" of Ahmad (6510) and "Sahih Ibn Hibban" (1881).