The epistle is one of four deuterocanonical books found among the Dead Sea scrolls (see Tanakh at Qumran). (The other three are Psalm 151, Sirach, and Tobit.) The portion of the epistle discovered at Qumran was written in Greek. This does not preclude the possibility of the text being based on a prior Hebrew or Aramaic text. However, the only text available to us has dozens of linguistic features available in Greek, but not in Hebrew; this shows that the Greek text is more than a minimalist translation.
The “letter” is actually a satire, or harangue, against idols and idolatry. Bruce M. Metzger suggests “one might perhaps characterize it as an impassioned sermon which is based on a verse from the canonical Book of Jeremiah.” That verse is Jer 10:11, the only verse in the entire book written in Aramaic.
Tell them this: “These gods, who did not make the heavens and the earth, will perish from the earth and from under the heavens.”
— Jeremiah 10:11
The work was written with a serious practical purpose: to instruct the Jews not to worship the gods of the Babylonians, but to worship only the Lord. As Gifford puts it, “the writer is evidently making an earnest appeal to persons actually living in the midst of heathenism, and needing to be warned and encouraged against temptations to apostasy.” The author warned the Hebrew exiles that they were to remain in captivity for seven generations, and that during that time they would see the worship paid to idols.
Readers were extolled not to participate, because the idols were created by men, without the powers of speech, hearing, or self-preservation. Then follows a satirical denunciation of the idols. As Gifford explains, in this folly of idolatry “there is no clear logical arrangement of the thought, but the divisions are marked by the recurrence of a refrain, which is apparently intended to give a sort of rhythmical air to the whole composition.” The conclusion reiterates the warning to avoid idolatry.