Welcome to Embrace Shabbat.
Therefore, it is ideal to eat Melaveh Malka in the hour after Shabbat, which has the power to knock out that additional force.
Rav Palagi teaches that every Friday afternoon at Chatzot, Hashem sits on the כסא של רחמים, His throne of mercy. In our tefillos we say, קל מלך יושב על כסא רחמים. The numerical value of קל is 31, hinting to the fact that the King sits on his chair of mercy for 31 hours, connecting to the 31 hours of Shabbat. This is why we say in our Shabbat prayers: ביום השביעי נתעלה וישב על כסא כבודו, On Shabbat day, G-d sits on His throne of glory. This, too, takes place during the 31 hour period of Kedusha.
We know that one should be careful not to get angry on Shabbat, as it says לא תבערו אש בכל מושבותיכם ביום השבת, do not ignite a fire in your dwellings on Shabbat. On the most basic level, this refers to Shabbat. However, Rav Palagi extends this idea to mean that one should not get angry during the 31 hours of Kedusha. The numerical value of לא in לא תבערו אש is 31. The Gemara teaches that the Satan tries to get us angry on Erev Shabbat, when we are preparing for Shabbat. Rav Palagi is teaching that a person must be careful with their anger from Chatzot on Friday until 1 hour after Shabbat, because whenever there is a force of Kedusha, there is also a force of tuma to counteract it.
In these 31 holy hours, we have the ability to connect to HaKadosh Baruch Hu’s rachamim. Rather than get angry, we should sing zemirot on Shabbat. ואתה קדוש יושב תהילות ישראל, G-d is holy. He dwells in the songs of the Jewish people.The Tosafot in Sanhedrin quotes from the Geonim to explain why they only said Kedusha on Shabbat in Eretz Yisrael. The angels lost a wing and only had 6 wings- the seventh wing was given to the Jewish people on Shabbat, and therefore they sang praise to Hashem. Because the Jewish people sing praise to Hashem, G-d dwells within them. The final letters of the words קדוש יושב תהילות spell Shabbat. Shabbat is the time that G-d sits on His throne, because of the תהילות ישראל.
I don’t have a source for singing songs on Erev Shabbat, but there is definitely a custom to sing on Motzei Shabbat. During these 31 special hours, G-d is sitting on His throne of mercy. At this holy time, we shouldn’t get angry, and then we will be able to knock out these negative forces- it is a time of song.
Have a Shabbat Shalom.