The hyperbole in these words of praise to Naomi sounds to be rather overdone in a Bantu context. No mother would be expected to value a daughter-in-law more than her own children, particularly in a matrilineal situation (as most of the tribes are in Central Africa), where a man’s offspring are reckoned as part of his wife’s family line and not his own. In effect, he begets children on behalf of another clan group; in other words, a daughter-in-law would be bearing for the lineage of another woman. This would not, however, lessen the joy that a woman would have at becoming a grandmother for the first time. In an African society, the relations between grandparents and grandchildren are especially close (paradoxically, they interact with each other as “age-mates”), and the former often do “take care of” (v. 16, Good News Bible) the latter in a village setting.
Source: Wendland 1987, p. 185.