Variantly: "until Dan" ("ad Dan"). The tribes had not yet come to the land, and Eretz Yisrael had not yet ("adayin" [acronymic of "ad dan"]) been apportioned among the tribes. What, then, is the intent of "ad Dan"? The L–rd had said to Abraham: Twelve tribes are destined to issue from your loins, and this is the portion of one of them.
Long Before the Conquest, Long Before Joshua Crossed the Jordan, God
Mekhilta Tractate Amalek 2:20