3,980. Entering the Kodesh and the Kodesh HaKodashim

Hilchos Bias HaMikdash 2:3

If a kohein—whether a regular kohein or a Kohein Gadol—enters the Holy of Holies on any day other than Yom Kippur, or if a Kohein Gadol enters on Yom Kippur but not at the time called for by the service, he is subject to the penalty of a divine death as per Leviticus 16:2: “so that he not die.” The Kohein Gadol enters the Holy of Holies four times on Yom Kippur, as will be discussed IY"H in Hilchos Avodas Yom HaKippurim. If he enters a fifth time, he is subject to a divine death penalty.

Hilchos Bias HaMikdash 2:4

If someone enters the Sanctuary (the Kodesh) other than to perform the service or to prostrate, regardless of whether he’s a regular kohein or a Kohein Gadol, he is subject to the penalty of lashes rather than a divine death, as per the aforementioned verse: “…before the Ark cover so that he not die.” We see that one is liable to a divine death only for entering the Holy of Holies, but doing so in the rest of the Temple is the violation of a prohibition, which is punishable by lashes.