In the recent volume of the Joseph Smith Papers, we have this useful background to D&C 129:
JS’s remarks in
February 1843 centered on an explanation of the ways to distinguish between various
types of heavenly messengers and the devil. Among eighteenth- and nineteenth-century
Protestants , there were several competing ideas about the identification of
angels, most of them based on a passage in the epistle to the Hebrews that mentions
“an innumerable company of angels” and the “spirits of just men made perfect”
(Hebrews 12:23-23). Some religionists held that these verses refer to “those
translated to heaven in their bodies, and those raised from the dead after
Christ’s resurrection” (Alexander Campbell, “Materialism—No. 2,” Millennial Harbinger,
Oct. 1836, 456). Others believed they
refer to more generally to “all in every age and nation who have feared God and
wrought righteousness” (MacKnight, New Literal Translation, 572). Theologians
also debated the substance and materiality of angels. Eighteenth-century
Swedish mystic Emmanuel Swedenborg suggested that angels were corporeal beings
who had lived on the earth and could converse with men face-to-face. While
those who believed angels were translated or risen beings seemingly believed
that all angels were corporeal beings, some concluded that “angles have no
corporeal forms” (Stuart, Letters on the Trinity, 111). Theologian Charles Buck explained that “as to the nature of these beings
we are told that they are spirits,” with the “more general opinion” being that “they
are substances entirely spiritual.” At the same time, Buck allowed that “they
can at any time assume bodies and appear in human shape” (“Angel,” in Buck, Theological
Dictionary, 19, italics in original).
JS suggested a new
idea, which classified heavenly messengers as either resurrected corporeal
beings or disembodied spirits awaiting resurrection. These distinctions may
have appeared in Latter-day Saint theology as early as 1829, when the Book of Mormon
suggested a difference between “angels and ministering spirits” (New Testament
Revision 2, p. 138 [second numbering] [Joseph Smith Translation, Hebrews 1:7]).
In his 27 June 1839 discourse, JS emphasized that “an angel of God (which is an
angel of light) is a Saint with his resurrected body” but also noted that it
was possible to be visited by deceased believers who were not yet resurrected. JS used this occasion in February 1843 to
refine that explanation by distinguishing between “resurrected personages” and “the
spirits of just men made perfect” who were still awaiting resurrection.
In addition to
teaching periodically about the ways to distinguish between types of angels. JS
had demonstrated a long-standing interest in recognizing the differences
between true and false spirits. A circa 8 March 1831 revelation urged the
Saints to “beware lest ye are deceived” and to do “all things with prayer &
thanksgiving that ye may not be seduced by evil spirits or the doctrines of
Devils or the commandments of men for some are of men & others of Devils” (Revelation,
ca. 8 Mar. 1831-A, in JSP, D1:282 [D&C 46:7-8]). A revelation the
following May was even more specific, explaining, “There are many spirits which
are false spirits which have gone forth in the Earth deceiving the world &
also Satan hath sought to deceive you that he might overthrow you” (Revelation,
9 May, 1831, in JSP, D1:306 [D&C 50:2-3]). In April 1842 JS reiterated
this message in a lengthy editorial in the church newspaper, urging the Saints
to “try the spirits” (selections from Times and Seasons, 1 Apr. 1842, in
JSP, D9:324-337). The, recounting portions of his own personal history
to the Saints in a September 1842 letter, JS alluded to an early experience “on
the banks of the Susquehanna” when the devil had appeared to him “as an Angel
of light” (Letter to the Church, 7 Sept. 1842, pp. 66-67 [D&C 128:20]). (Spencer
W. McBride, Jeffrey D. Mahas, Brett D. Dowdle, and Tyson Reeder, eds., The
Joseph Smith Papers: Documents Volume 11: September 1842-February 1843
[Salt Lake City: The Church Historian's Press, 2020], 402-3)