the destruction of jerusalem continues to burn.
and casts a shadow.
even over something that should be delightful.
(discussion about preparation for shabbat, and the importance & reward of honouring shabbat, leads to a statement that where there is desecration of shabbat there is a destructive fire that cannot be put out. this in turn leads to various theories as to why Jerusalem was destroyed. for english translation of this talmud page, see here)