Siman 387

The matter of overturning the bed mentioned in the Gemara appears to be for two reasons. One: because it was their custom to sit upon the beds. Since the mourner must sit upon the ground, he therefore overturns his bed. Evidence for this is from what they said (Moed Katan 27a) that on the eve of Shabbat from the time of Mincha and onwards one sets the beds upright, and nevertheless he does not sit upon it until it grows dark, see there. It follows that the overturning is for the sake of the sitting. Regarding this, Tosafot wrote there (under the heading "From the time of Mincha") and this is their wording: It appears to me that from here they relied [on the custom] not to sit upon a chair or a bench, etc., see there.

However, it is not for this reason alone that there is the overturning of the bed, for they said there (Moed Katan 21a) that even if he sat and slept upon the ground, he has not fulfilled his obligation if he did not fulfill the overturning of the bed, see there. And the reason for the overturning of the bed is as Bar Kappara taught (Moed Katan 15a), that this is, as it were, as the Holy One, Blessed be He, says: "I placed the likeness of My image among you, for in the image of God He made man, and through your iniquities I have overturned it; overturn your beds because of it," see there. Therefore, our Sages, of blessed memory, said (Moed Katan 27a) that it is not only his own bed that he overturns, but rather all beds that he has within his house, except for a bed used for vessels.

And now we do not practice the overturning of the bed for two reasons: One, that our beds are not made like their beds, such that overturning would be applicable to them. And furthermore, that the gentiles would wonder and say that there is some kind of sorcery in this. And in my opinion there is another reason: because our sitting is not upon beds, and among us we sit upon the ground. And not specifically upon the ground, but rather upon a small bench, or upon pillows and blankets (the Gaon Rabbi Akiva Eiger). And there are those who require specifically upon the ground (see Shach). But from the Yerushalmi at the beginning of the third chapter of Berakhot, it seems to me there is proof that it is not so, for we learn there that it is written regarding Job: "And they sat with him to the ground" — "upon the ground" is not written here, but rather "to the ground," something that is close to the ground, see there. And one who is weak in his health or a pregnant woman — they shall not sit at all upon the ground but rather upon a high place. And regarding sleep, there are those who are stringent to sleep upon the ground (see Shach), and there are those who are lenient (Panim Me'irot) and such is the custom. And on the eve of Shabbat, some hours before nightfall, they shall rise from the ground, and close to the lighting of the candles they shall put on shoes.