Q: Do I need permission to forward an email?
A. Forwarding an email without the permission of the sender can involve
a number of ethical problems related to revealing information
transmitted in confidence.
One specific Jewish stricture "forwards" run afoul of is the famous
"ban" of Rabbenu Gershom. Rabbenu Gershom, was a leading Rabbinic leader in 10th century Germany. Among the many decrees he instituted is one on reading the private letters of other people. (1) To this day many people passing notes or letters remind
others of their desire for privacy by writing the Hebrew acronym "CDRG":
Cherem deRabbeinu Gershom (Rabbi Gershom's ban).
Another source is the following passage from the Talmud:
Rabba stated: From where do we learn that if someone says something to
his fellow, it is forbidden to reveal it until he tells him "say"? As it
is written (Leviticus 1:1): "And the Lord spoke to him in the Tent of
Meeting, to say." (2)
While grammarians generally interpret the Hebrew expression "to say" as
the equivalent of quotation marks, introducing an exact citation, the
rabbinical tradition is that this expression means that the speaker
(usually G-d) is telling the listener (usually Moses) to say something:
either to pass along His words or to bring Him the reply of the
listeners. We can infer that without explicit authorization, one should
generally refrain from passing on private communications.
As some commentators point out, this explanation is a bit cryptic in
reference to this particular verse, for the very next verse states
explicitly: "Speak to the children of Israel, and say to them . . ." So
even without the addition "to say" Moses would certainly know that he
has to repeat G-d's command!
I would like to suggest the following resolution to this paradox. There
are two different levels of transmission. One is to summarize and reword
the message the listener received. This is a less intrusive kind of
revelation, for two reasons: one reason is that less information is
revealed, and the other is that the exact words aren't mentioned so that
the original speaker is not so pinned down; he maintains a degree of
"plausible deniability." For example, he can claim that he was misunderstood, taken out of
context and so on.
When G-d tells Moses to speak to the children of Israel and transmit the
commandments relating to the sacrifices, Moses can fulfill this by
summarizing or paraphrasing the original prophecy. (Our tradition states
that the prophecy of Moses, unlike that of the other prophets, took the
form of exact words, not merely of visions then expressed in the
particular speaking style of the prophet.) (3) The additional words "to
say" create a mandate to transmit G-d's exact words. (This explanation
harmonizes the traditional understanding of the expression "to say" and
the grammatical one.)
From this we can learn that even if someone might not mind having his
message transmitted to someone else "in the loop," he or she might still
object to having the exact words of the original email sent ahead.
The moral of the story is that we should be very careful not to forward
emails unless we are sure the sender approves. Even when it is clearly
appropriate to transmit the message to others, consider if it may not be
sufficient to provide a brief summary of the sender's words, rather than
just forwarding the exact words. Likewise, even when forwarding
someone's exact words, don't forward the whole letter if the really
relevant section is brief.
SOURCES: See for example Beer HaGolah commentary on the end of
Shulchan Aruch, Yoreh Deah 334. (2) Babylonian Talmud, Yoma 4b. (3) Midrash Pesikta Zutreta on Exodus verse 9:14