Jeffrey M. Bradshaw describes some of the reasons Joseph Smith may have been interested in Freemasonry.
Jeffrey M. Bradshaw, Freemasonry and the Origins of Latter-day Saint Temple Ordinances (Orem and Salt Lake City, UT: The Interpreter Foundation and Eborn Books, 2022), 33–36
Lost keys of knowledge. Though the proportion of authentic teachings and ritual practices transmitted to Masonry intact from ancient times may be much smaller than what was believed both by many early Freemasons and many early members of the Church, late statements by Elder Franklin D. Richards and others—both Saints and skeptics—suggest that Joseph Smith believed that there were at least some ancient things in Freemasonry he wanted either to discover or confirm through his own personal participation in Masonic rites, coupled with prayerful inquiry and resulting revelation:
• Elder Franklin D. Richards:114 Joseph, the Prophet, was aware that there were some things about Masonry which had come down from the beginning and he desired to know what they were, hence the lodge. The Masons admitted some keys of knowledge appertaining to Masonry were lost. Joseph enquired of the Lord concerning the matter and He revealed to the Prophet true Masonry, as we have it in our temples.115
• Elder Franklin D. Richards:116 I spoke of … some of the circumstances which led up to the Prophet Joseph asking of the Lord & obtaining promise to restore that which was lost indeed.
• J. H. Beadle:117 Joseph Smith out-masoned Solomon himself and declared that God had revealed to him a great key-word, which had been lost.
• Richard F. Burton:118 The angel of the Lord brought to Mr. Joseph Smith the lost key-words of several degrees.
• John C. Bennett:119 Joe pretends that God has revealed to him the real Master’s word.
These statements should be compared with Book of Abraham, Facsimile No. 2, Fig. 7: “Represents God sitting upon his throne, revealing through the heavens the grand Key-words of the Priesthood.”
Preparing the Saints for the temple. Evidence additionally suggests that Joseph Smith encouraged Nauvoo Masonry at least in part to help those who would later receive temple ordinances. For instance, Joseph Fielding, an endowed member of the Church who joined Freemasonry in Nauvoo, said: “Many have joined the Masonic institution. This seems to have been a stepping-stone or preparation for something else, the true origin of Masonry”—that is, in authentic, ancient priesthood ordinances to which some elements of Masonic rites bore resemblance.120 Among other things, this preparation seems to have included:
• Gaining experience with covenants of confidentiality. One aspect of this preparation apparently had to do with the general idea of respecting covenants of confidentiality. For example, Joseph Smith once told the Saints that “the reason we do not have the secrets of the Lord revealed unto us is because we do not keep them.”121 But as he later observed, “The secret of Masonry is to keep a secret.”122 Joseph may have seen the secret-keeping of Masonry as a tool to prepare the Saints to respect their temple covenants.
• Gaining familiarity with learning through ritual. The rituals of the Lodge enabled Latter-day Saint Masons to become familiar with symbols and forms they would later encounter in the Nauvoo temple. These included specific ritual terms, language, handclasps, and gestures as well as larger patterns such as those involving repetition and the use of questions and answers as an aid to teaching. As stated above, Joseph Smith’s exposure to Masonry no doubt led him to seek further revelation as he prepared to introduce the divinely revealed ordinances of Nauvoo temple worship.
All this said, none of the many contemporary Mormon Masons who remained faithful to the Prophet following their temple endowment expressed a concern that Joseph Smith had been untrue to his Masonic obligations by incorporating some Masonic elements into the endowment ceremony.123 Moreover, it appears that the obligations accepted in the Lodge were taken seriously by faithful Latter-day Saints, both before and after their endowment.124 Latter-day Saint historian Richard L. Bushman observed: “If Joseph thought of Freemasonry as degenerate priesthood, he did nothing to suppress his rival.”125 In support of this claim, note that interest in Masonry did not suddenly disappear after the temple endowment was introduced. Rather, it continued in Nauvoo until the departure of the Saints in February 1846.126
Significantly, Andrew F. Ehat notes how the contents of a letter from longtime Mason Heber C. Kimball to Parley P. Pratt on 17 June 1842 testify of:127
the Prophet’s ease in pointing out the relationship of the endowment to Freemasonry in what might otherwise have been considered a blatant adaptation of Freemasonry[. This] demonstrates the awe and respect Heber Kimball and the others had for what has been a troublesome point to informed . . . Latter-day Saints [in more recent times]. These Freemasons who received these blessings in May 1842 completely accepted Joseph Smith’s self-characterization as expressed in an 1844 discourse: “Did I build upon another man’s foundation, but my own? I have got all the truth [offered by the world] and an independent revelation in the bargain.”128
What did Joseph mean when he spoke of not building on another man’s foundation? The context of the statement above is not completely clear, but Don Bradley posits129
he means having only secondhand knowledge of the divine. Because Joseph was getting all the truths others had and getting revelation, he had both, which he clearly frames as being better than just having one or the other.
Thus, the idea in Joseph’s declaration isn't that his gathering of humankind’s truths isn't important, but that it isn’t enough. One also needs direct divine communication. Just as the Doctrine and Covenants tells us to obtain knowledge by study and by faith,130 we need both avenues of acquiring truth. And, just as the Lord’s instructions to Oliver Cowdery about how to translate tell him to “study out” revelation, these two modes of acquiring knowledge are part of one another. Joseph builds his edifice on divine authorization and a constant search for inspiration—this is his foundation, and he builds with bricks that are, comprised in part of the “all the truth” he was able to obtain from within the human world.
The effective manner by which the Prophet combined truths that “others had” with the additional results obtained from the “independent revelation” explains the impressions of endowed members who saw the Nauvoo temple ordinances as something more than what they had experienced as part of Masonic ritual. Hyrum Smith, a longtime Mason, expressed the typical view of the Saints about the superlative nature of the temple blessings when he said: “I cannot make a comparison between the house of God and anything now in existence. Great things are to grow out of that house; there is a great and mighty power to grow out of it; there is an endowment; knowledge is power, we want knowledge.”136