But, let’s just focus on the beginning:
The Mishnah states that is forbidden for a man to go out in public on Shabbat wearing implements of war (sword, bow, shield, lance or spear). Now these many be considered “ornaments” (which would be permissible) but they are not allowed because they are “shameful.”
Why are they “shameful”? Because Shabbat is considered a foretaste of the messianic era, which the prophet describes in the famous vision: “Nation shall not lift up sword against nation, neither shall they learn war anymore.” (Isaiah 2:4) So wearing items of war – even ornamental ones – on Shabbat is an insult to that vision.
But what if they are considered beautiful? Abaye says “It may be compared to a candle at noon.” I love that – while a candle looks beautiful at night, at midday it is irrelevant. Context matters!
Notice that neither the Mishnah nor Gemora say anything here about self-defense. It is just assumed that no one would want or need to be armed on Shabbat. The peacefulness of the day is like the sun shining at noon.
So for gun supporters – a least let’s have one day of rest!