Glossa Ordinaria

Mary, etc. The Virgin is distinguished from the women, who nevertheless is sometimes called a woman not for corruption, but for sex. Behold, the beginning of the newborn Church is adorned with the flower of virginity. In the midst of the brethren. That is, of sons, whose Father in heaven is one. Peter is said to have stood in the midst: as though condescending with a common compassion. This example is to be taken up by the shepherds of the Church. This number of a hundred and twenty agrees with the age of Moses, so that, as under this number, Moses having died, Jesus succeeded, who led the people into the land of promise, so the sovereignty of Christ succeeded the old law in the Church, leading the true Israel to the kingdom of heaven.