1) AGADAH: TAKING LEAVE OF ONE'S FRIEND WITH "L'SHALOM" AND NOT "B'SHALOM"
QUESTION: Rebbi Levi bar Chaisa teaches that when one parts with the deceased, he should not say, "Lech l'Shalom" ("Go towards peace (peacefully)"), but rather, "Lech b'Shalom" ("Go in peace").
In contrast, when one parts with his friend, he should not say to him, "Lech b'Shalom" ("Go in peace"), but rather, "Lech l'Shalom" ("Go towards peace (peacefully)").
The VILNA GA'ON (quoted by the Pardes Yosef) points out that Rebbi Levi bar Chaisa's teaching explains the verse that describes the brothers' enmity towards Yosef: "And they hated him, and they could not speak with him peacefully (l'Shalom)" (Bereishis 37:4). Out of their contempt for Yosef they could not bring themselves to bless Yosef with the word "l'Shalom" as one speaks to the living, but rather they preferred to treat him like a dead person.
This raises a question in a different verse. If one is not supposed to bless his friend with the word "b'Shalom," then why did Yakov Avinu ask Hash-m to return him "in peace" ("b'Shalom") to his father's home (Bereishis 28:21)?
ANSWERS:
(a) To answer this question, it is necessary to understand the reason for why one should bless the living with the word "l'Shalom" and not with the word "b'Shalom." The SEMICHAS CHACHAMIM (to Berachos 64a, by Rav Naftali Kohen of Frankfort) explains that a living person must always seek to grow spiritually and avoid stagnating on the same spiritual level. A dead person, in contrast, can no longer grow and achieve; he remains at whatever spiritual level he attained in his lifetime. For this reason, the blessing given to a living person is, "Go towards peace" ("l'Shalom") -- towards a greater level of spiritual wholeness ("Shalom" from the word "Shalem," whole). In contrast, the blessing given to the deceased is, "Go in peace" ("b'Shalom"), since his soul leaves this world at the level of spiritual accomplishment that he achieved in his lifetime.
This explains why Yakov Avinu did not use the prescribed terminology in his prayer. Normally, one blesses another person that he should grow and rise higher. Yakov Avinu was about to embark on his journey to the house of Lavan, a place full of wickedness and impurity. He prayed, "May I return in peace" ("v'Shavti v'Shalom") -- "may I return from the house of Lavan on the same spiritual level at which I am now, unharmed and uninfluenced by the perilous environment there." (KOHELES YITZCHAK to Parashas Vayetzei)
(b) The RITVA and CHIDUSHEI HA'RAN give another explanation for the difference between "l'Shalom" and "b'Shalom." When one says to his friend, "Go in peace," he implies that he friend should have peace only while traveling. He does not include in his blessing what will happen once his friend reaches his destination. "Lech b'Shalom" is a blessing only for a peaceful journey, and not for a peaceful arrival. It is an incomplete blessing to give to the living. Besides blessing the traveler that his journey should be peaceful, one should bless him that he "go towards peace" and arrive at his destination in peace and suffer no harm there.
In contrast, "go in peace" is an appropriate blessing to the deceased. His destination (the World to Come) is certainly peaceful; it is only the journey there which is fearful (as the Gemara earlier (28a) describes).
According to this explanation, perhaps the Gemara's teaching applies only when the word "Lech" ("go") is used with the word "b'Shalom." The word "Lech" implies that the ordeal of the journey alone should be peaceful. When Yakov Avinu said, "I should return b'Shalom," without the word "go," he meant that his arrival back home should be in peace. In the context of his prayer, the word "b'Shalom" was appropriate.
(c) Alternatively, perhaps Yakov Avinu used the word "b'Shalom" because his prayer indeed included a request to be returned to his father's house after his death. Yakov Avinu prayed that Hash-m allow him to be buried in the Cave of Machpelah alongside his father. (This wish was granted to him when Esav accepted all of Yakov's wealth in return for his portion in the Cave; see Rashi to Bereishis 50:5). (M. Kornfeld)