Noble states that JS taught him about plural marriage in the fall of 1840; says JS was commanded to practice it by an angel.
Joseph B. Noble, Affidavit, June 26, 1869, Affidavits about celestial marriage, 1869-1915, 40 Affidavits on Celestial Marriage, Book number 1, 1869, 38–39, MS 3423, Church History Library
Territory of Utah} ss.
County of Salt Lake}
Be it remembered that on this twenty-sixth day of June A.D. 1869—personally appeared before me, James Jack, a Notary Public in and for said county, Joseph Bates Noble, who was by me sworn in due form of law, and upon his oath saith that, in the fall of the year A.D. 1840 Joseph Smith taught him the principle of celestial marriage or a "plurality of wives," and that the said Joseph Smith declared that he had received a revelation from God on the subject, and that the angel of the Lord had commanded him (Joseph Smith) to move forward in the said order of marriage, and further, that the said Joseph Smith, requested him (Jos. Bates Noble) to step forward and assist him in carrying out the said principle, saying, "in revealing this to you, I have placed my life in your hands, Therefore do not in an evil hour betray me to my enemies."
Subscribed and sworn to}
by the said Joseph B. Noble} Joseph B. Noble
the day and year first above written}
James Jack
Notary Public