Here the earliest textual source, the printer’s manuscript, reads swear, but this is an error for the past-tense form sware (the result of swear and sware being homophones of each other). The misspelling probably originated in 𝓞 as Oliver Cowdery took down Joseph Smith’s dictation. In the third printing (in 1907) of the 1905 LDS edition, swear was replaced by the modern-day pasttense form swore. The LDS text has continued with swore, but the critical text will restore the original sware here. For another example of swear as a misspelling for sware, see under Ether 8:14; for a general discussion on the competition between sware and swore in the history of the text, see under Enos 1:14.
Summary: Restore the original past-tense form sware in Ether 1:33.