Two Are Better Than One
Regarding the laws of Shabbat, if one wishes to avoid a Torah violation, he can have a friend participate in what he is doing.
For example, it is forbidden to carry from a private to a public domain on Shabbat if there is no Eiruv. However, if two people carry together something that could be carried by one person, they are exempt from the severe penalty of Shabbat violation. The act would still be rabbinically forbidden.
This is learned from a Pasuk in Vayikra that speaks about accidental transgressions. The Torah says that if a person sins accidentally, when he violates one of the commandments. The word for, “when he does” a transgression, is, ״בעשותה״. The Talmud in Masechet Shabbat points out that this word is intentionally written in the singular.
It is to teach that there is a violation if one person does the act, and not two. This is called, “ זה יכול וזה יכול. This implies that each could do the act by himself.
However, if it is a situation of זה יכול וזה אינו יכול, where one could have done the act by himself, and the other cannot, this would not remove the status of inadvertent Shabbat violation. The transgressor would need to offer a חטאת, a sin offering, to achieve atonement.
It is interesting how one word, בעשותה, could have such far reaching implications. This is but another proof that we must study the Torah in greater depth, to truly understand its teachings.