Genesis 1:18

¹⁸ And to rule over the day and over the night, and to divide the light from the darkness: and God saw that it was good.

Three and a half

In Revelation 11:9, this signifies to the end and the beginning, or to the end of the present church and the beginning of a new church. (Apocalypse Revealed 505) It also signifies the same as a week because it is half of seven. (Apocalypse Revealed 505[2])

⁵ To him that by wisdom made the heavens: for his mercy endureth for ever.