Genesis 25:16
These are the sons of Ishmael, and these are their names, by their towns, and by their castles; twelve princes according to their nations.
Cross-reference
Genesis 17:20
Prophetic fulfillment
In Genesis 17:20, God promised Ishmael would father twelve princes. This list of twelve princes fulfills that promise.
Genesis 37:25
Historical context
In Genesis 37:25, an Ishmaelite caravan passes Joseph — descendants of these twelve clans who formed trading companies.