פירוש על קידושין 73:16

In the baraita, R. Yishmael was referring to the libations brought with offerings (Numbers 15:2). But in this verse two words are used to indicate that the obligation occurs only in the land—תבואו, which means “enter” and “מושבותיכם” your settlements. For the rule to apply both of these words need to be used. If only “settlements” is used, then the mitzvah might apply outside the land.