http://revach.net/article.php?id=4982

Section: Parshas HaShavua   Category: Quick Vort
Parshas Vayakhel - Rav Yehonoson Eibshitz - Fire Comes After The First Shabbos

"Lo Sivaaru Eish Bichol Moshvoseichem BiYom HaShabos," (Vayakhel 35:3). The only Milacha of Shabbos singled out in the Torah is lighting a fire. Why?

Rav Yehonoson Eibshitz explains that in the first Luchos it says that we rest from work on Shabbos because Hashem rested after six days of creation. On Shabbos, we refrain from performing anything pertaining to those first six days. However, fire was created on Motza'ei Shabbos. Therefore, we may think it stands outside the prohibition of doing Milacha, so the Torah must tell us that even lighting a fire is assur on Shabbos.