How can we tell that this is Shabbos?

Hi,

[Yes, the following requires some commentary...]

"Wicked Turnus Rufus also asked this question of Rabbi Akiva: Why is one day different from other days? He replied: Why are you different from other men?

"He replied: Because my master [Caesar] wishes it. [Rabbi Akiva:] The same is true for Shabbat; my Master wishes it.

"Turnus Rufus said: This is what I mean to ask: Who says that today is Shabbat? Rabbi Akiva replied: The Sabatyon River proves it [for it rests on Shabbat], the baal ov proves it [speaking to the dead is not effective on Shabbat], and your father's grave proves it for it does not produce smoke on Shabbat.

"He replied: You have disgraced him, you have shamed him, you have cursed him!"

(Talmud, Sanhedrin 65b)

Have a great day,

Mordechai