3 From Antioch be betook to the desert of Chalcis, in Syria, to perfect himself in his knowledge of the Bible, and at the same time to curb "youthful desires" by means of hard study. Here he engaged a convert Jew to teach him Hebrew and Chaldaic. What a toil it was! How difficult I found it! How often I was on the point of giving it up in despair, and yet in my eagerness to learn took it up again! Myself can bear witness of this, and so, too, can those who had lived with me at the time. Yet I thank God for the fruit I won from that bitter seed.
Source: Spiritus Paraclitus (Vatican.va)