This week's portion opens with the commandment of observing Shabbos (Ex. 35:1-3). One of the verses states, "You may not kindle a fire in any of your dwellings on the Sabbath day" (Ex. 35:3). In the Tikkunei Zohar (Tikkun 48, pg. 85a) it says that this verse is not only warning us from lighting a flame of fire on Shabbos, but it is also cautioning us from kindling the fire of anger on Shabbos.
In general, the fires of Gehennom (purgatory) stop burning on Shabbos. However, if a person allows himself to get angry on Shabbos, he rekindles the fires of Gehinnom. Not only that, but getting angry brings the fires of Gehinnom into one's house.
The Shvilei Pinchas adds that, typically speaking, most people are found at home on Shabbos. This increases the likelihood of argumentativeness. Therefore, we are being warned against getting angry especially on Shabbos.
Actually, we are warned about the dangers of anger even on erev Shabbos (Friday afternoon, Mishna and Gemara Shabbos, chap.2, "Bameh Madlikin", Mishna 7, pg. 34a, Rabba bar Rav Huna, Rav Ashi, Rashi). This is because a fight on erev Shabbos can spill over into Shabbos, ruining the holy Sabbath atmosphere.
As a matter of fact, the entire institution of lighting Shabbos candles was in order to preserve Shalom Bayis (peace at home). This goal is so great that if one has only enough money to purchase Shabbos candles or Channuka candles, or if one has only enough money to buy candles or wine for Kiddush, acquiring the Shabbos candles takes precedence (Shabbos, chap.2, "Bameh Madlikin", pg.23b, Rava).
Moreover, the Zohar (Yisro, pg. 88a) teaches that any success or blessing during the week is dependent upon our behavior on the previous Shabbos. Therefore, strife on Shabbos can ruin a person's entire week.
Additionally, conflict on Shabbos can even affect the following Shabbos in a negative way (See Shabbos, chap. 16, "Kol Kisvei", pg. 119b, Rebbi Yosi bar Yehuda). This creates a vicious cycle.
This is why the Satan tries to inject Jewish homes with quarrels on Friday afternoons. It is because he wants to destroy our lives. There is a story in the Talmud which reveals this to us.
Once upon a time, there were two people, (a husband and a wife; Iyun Ya'akov), whom the Satan would incite every erev Shabbos. As a result, they would always wind up arguing with each other. Rebbi Meir found out about them and appeared at their doorstep one fine Friday afternoon. Rebbi Meir asked if he could spend the day with them. They acquiesced. Since they were in the presence of such a great man, they went about their Shabbos preparations without criticizing each other. This scenario repeated itself three weeks in a row, until the Satan left their home and peace was restored between the couple (Gittin, chap.5, "Hanizkin", pg. 52a).
I would like to point out that the Gemara has no interest in gossiping about some random couple. The reason why the sages of the Talmud shared this story is because they realized that this may be relevant to many of us. Knowledge of the Satan possibly entering into our own homes in order to create friction is supposed to heighten our awareness to become even more sensitive to this danger and try to avoid it at all costs.
Apparently, Rebbi Meir made it a habit trying to help bring peace between people, especially between husbands and wives. The following story illustrates this.
Once upon a time, Rebbi Meir was delivering a Torah lecture in a shul on Friday night. After he finished, one of the women who attended the class returned home. She arrived so late that her Shabbos candles were already extinguished. Her husband, who had been sitting there all alone, asked her where she had been. She said that she had attended Rebbi Meir's lecture. The husband was so angry that he said that she could not stay in his house until she spat in Rebbi Meir's face.
After the wife was kicked out of the house, Eliyahu Hanavi appeared to Rebbi Meir and told him that because of his lecture, a woman was expelled from her home by her husband. Rebbi Meir felt terrible, so he went to the town's largest shul where it was common for homeless people to gather. Eventually, Rebbi Meir spotted the woman.
Rebbi Meir pretended that he had an eye infection. He called out to everybody in the shul asking them if they knew how to treat an eye infection. Nobody knew. Then, Rebbi Meir walked over to this woman and asked her if she knew how to treat an eye infection. She said that she did not. Rebbi Meir said that even so, he needed her to spit in his eye so that the saliva would ease his pain.
Hearing that Rebbi Meir needed her help, she obliged. Rebbi Meir put his head back and pulled his eyelids wide open and the woman spat in his eye. Rebbi Meir sat up, smiled, and said that if she wanted to, she could now go home and tell her husband truthfully that she had spat in Rebbi Meir's face (Devarim Rabba, 5:15).
It seems that Rebbi Meir went out of his way in order to bring peace between people. Why was Rebbi Meir so committed to this mission? This will become clear momentarily.
Rebbi Meir came from Roman converts (Gittin, chap. 5, "Hanizkin", pg. 56a). As such, Rebbi Meir was a descendant of Eisav. Not only was he a descendant of Eisav, but, kabbalistically speaking, Rebbi Meir's soul was buried within Eisav's mouth. This explains why Yitzchak loved Eisav (Gn. 25:28). The verse says that Yitzchak loved him because he "hunted with his mouth" (Gn. 25:28). The deeper meaning behind this is that Eisav had the spark of Rebbi Meir buried inside of his mouth. This is what Yitzchak loved about Eisav (Arizal, Likutei Torah).
Now, the Midrash says that Eisav is one who actually hates peace (Shocher Tov, Psa. 120:6). Therefore, the Shvilei Pinchas says that this is why Rebbi Meir bent over backwards to try and bring peace between people. It is because Rebbi Meir knew about his ancestry and about his connection to Eisav. Rebbi Meir was concerned that some of Eisav's character flaw, with respect to being anti-peace, would be passed down to him in his spiritual DNA. Therefore, Rebbi Meir did everything possible to distance himself from that and went to the other extreme in order to bring about peace.
Before concluding, I would like to share one more benefit to being extra careful with maintaining peace in the home specifically on erev Shabbos.
Every erev Shabbos, the Rebbe, Reb Elimelech of Lizhensk would approach his wife and he would begin to cry, begging her to forgive him in case he may have accidentally hurt her in any form or fashion during the week. He told his wife that the first sin of mankind was not eating from the Eitz Hada'as (Tree of Knowledge), because it could be argued that Hashem wanted them to eat from it eventually. Rather, the first sin was that Adam (who thought that it was wrong to eat from it) blamed his wife for making him eat from the tree (Gn. 2:12).
Reb Elimelech explained to his spouse that every Jewish husband and wife is a miniature Adam and Eve. This means that every Jewish couple stands a chance at rectifying the first mistake. The most opportune time to fix that error would be on erev Shabbos since that was precisely the time that Adam sinned by blaming his wife. They made a promise between themselves that they would try to never get upset at each other, especially on erev Shabbos.
This is another benefit to maintaining peace and harmony in our homes on erev Shabbos. Every single one of us can participate in repairing the damage that was wrought upon this world as a result of Adam and Eve's first fight.
The Belzer Rebbe Shlit"a suggested a segula (charm) to help couples from arguing on erev Shabbos. He said that every couple should read the story in the Talmud about Rebbi Meir appearing at that couple's doorstep every erev Shabbos (Gittin, 52A). On a practical level, this will help remind the couple about being cautious and strengthen them to avoid criticism at all costs. On a supernatural level, just reading this story may create an aura of peace which will permeate the home.
So, may we all be blessed to "Meir" (enlighten) the world with the light of peace and kick the Satan of argumentativeness out of our homes, and thus witness the blessings that will enter into our relationships, which will lead us into the era of Yom Shekulo Shabbos.