Core, the Levite, with Dathan and Abiram led two hundred and fifty of the people of Israel in a rebellion against Moses and Aaron (Numhers XVI: 3). Upon Moses' invocation, the earth split asunder and swallowed Core and his followers.
God showed His mercy to the sons of Core by lifting them up. The miniature represents the salvation of Core's sons, whose father disappears into the gaping earth while a tree splits.
It introduces Psalm XLV, one of those referred to in the psalter as "A Psalm for the Sons of Core": "Therefore we will not fear, when the earth shall he troubled..."
This and the two following miniatures are by the Limbourgs.

small image (21KB) --- large image (193KB) --- The sons of Core (large) (199KB)