Leviticus 13:47–50 --What was bad about mold? Regulations About Defiling Molds 47 “As for any fabric that is spoiled with a defiling mold—any woolen or linen clothing, 48 any woven or knitted material of linen or wool, any leather or anything made of leather— 49 if the affected area in the fabric, the leather, the woven or knitted material, or any leather article, is greenish or reddish, it is a defiling mold and must be shown to the priest. 50 The priest is to examine the affected area and isolate the article for seven days.
Leviticus 16:2
ESV - 2 And the Lord said to Moses, "Tell Aaron your brother not to come at any time into the Holy Place inside the veil, before the mercy seat that is on the ark, so that he may not die. For I will appear in the cloud over the mercy seat.
For follow-up discussion and general commentary on the topic. Comments are sorted chronologically.