In his editing for the 1837 edition, Joseph Smith changed the verb constrain to restrain in three places. In 2 Nephi 1:26, he marked the change in 𝓟, but here in Ether 12:2 (and also in Ether 13:31) the change appears first in the 1837 edition itself. As explained under 2 Nephi 1:26, the critical text will restore the original constrain in all three cases.