In Mechilta (to ex. 12.16), while discussing whether or not work is forbidden on chol hamoed, the time before and after the six days of creation are referred to as holy.
ששת ימי בראשית יוכיחו שיש קדושה לפניהם ולאחריהם ומותרים במלאכה
Obviously after creation creation refers to the seventh day when God rested; very holy. But what is the reference to being holy about prior to the six days? Is this a specific reference to something, or shall I just learn from here that it was a holy time (that is, before time).