Here "give away ... in marriage" is an idiom which means that he allowed his daughters to get married. Alternate translation: "He had thirty daughters and arranged a marriage for each of them" (See: [[rc://en/ta/man/translate/figs-idiom]])
The idiom "bring them in from the outside" means that he had women from other clans marry his sons. Alternate translation: "he arranged for thirty daughters of other men from outside of his clan to marry his sons" (See: [[rc://en/ta/man/translate/figs-idiom]])