Philo Judaeus De Mutatione Nominum 143

[143] and to those who ask, whether she who is barren has an offspring (for the holy scriptures, which some time ago represented Sarrah as barren, now confess that she will become a mother); this answer must be given, that a woman who is barren cannot, in the course of nature, bring forth an offspring, just as a blind man cannot see, nor a deaf man hear; but that the soul, which is barren of bad things, and which is unproductive of immoderate license of the passions and vices, is alone very nearly attaining to a happy delivery, bringing forward objects worthy of love, namely, the number seven, according to the hymn which is sung by Grace, that is, by Hannah, who says, "she who was barren hath born seven, and she who had many children has become weak:" ¹