3 I have nearly wandered into a new subject, and while I have kept my wheel going, my hands have been moulding a flagon when it has been my object to frame an ewer. For, in answer to your prayers and those of the saintly Marcella, I wish to address you as a mother and to instruct you how to bring up our dear Paula, who has been consecrated to Christ before her birth and vowed to His service before her conception. Thus in our own day we have seen repeated the story told us in the Prophets, of Hannah, who though at first barren afterwards became fruitful.
You have exchanged a fertility bound up with sorrow for offspring which shall never die. For I am confident that having given to the Lord your first-born you will be the mother of sons. It is the first-born that is offered under the Law. Samuel and Samson are both instances of this, as is also John the Baptist who when Mary came in leaped for joy. For he heard the Lord speaking by the mouth of the Virgin and desired to break from his mother's womb to meet Him. As then Paula has been born in answer to a promise, her parents should give her a training suitable to her birth.
Samuel, as you know, was nurtured in the Temple, and John was trained in the wilderness. The first as a Nazarite wore his hair long, drank neither wine nor strong drink, and even in his childhood talked with God. The second shunned cities, wore a leathern girdle, and had for his meat locusts and wild honey. Moreover, to typify that penitence which he was to preach, he was clothed in the spoils of the hump-backed camel.
Source: Letters (New Advent)