Praised be Jesus and Mary, now and forever.
The Church reveres St. Jerome as the greatest doctor God has given her for understanding the Bible. He was born around 347 in Stridon, in present-day Slovenia, to a Christian family. They gave him a very good education, hoping to prepare him for a career in the service of the Empire. They even sent him to Rome, where he studied under Aelius Donatus, the most famous Latin teacher of his day. 
In Rome, he felt the attraction of worldly life, but he also enjoyed visiting the catacombs. At 18, he was baptized by Pope Liberius. After his studies, he traveled, made friends, and deepened his commitment to Christianity, becoming involved in the monastic life. However, he still preferred to read Cicero's masterful Latin instead of the plain language of the Bible.
Traveling around in 375, he was in Antioch during Lent. In the middle of Lent, he fell gravely ill, so seriously ill that preparations were being made for his funeral. He found himself before Christ the Judge. He was asked about his status, and he replied that he was a Christian. And He who sat on the judgment seat said, "You lie. You are a Ciceronian, not a Christian. Where your treasure is, there is your heart also." The Judge ordered him to be flogged, and amid the lashes, he cried out for mercy. 
Others who were present at the scene knelt before the judgment seat and interceded for him, pleading his young age and asking that he be given time to repent. Jerome swore that he would never read pagan literature again, under pain of falling again under the same condemnation. When he had made this oath, the punishment stopped, and he returned to this world. Those at his bedside were surprised to see him reopen his eyes. His experience had been no mere dream or feverish delusion, as proven by the fact that his shoulders were black and blue from the blows, which he could still feel. 
He ends his story by saying, "After that, I read God's word with greater zeal than I had previously read the writings of mortals." It was not that there was nothing good in the classics. Certainly, there was, for he continued to quote them in his works. The problem was that he loved their words more than Jesus Christ's. 
After this, he went east into the desert of Chalcis, south of Aleppo, and lived there as a monk, a hermit, for a few years. He wore sackcloth, fasted severely, and battled temptations. Dedicating time to study, he improved his knowledge of Greek and began to study Hebrew with another monk. He wrote a life of St. Paul of Thebes. This was something he did to promote the monastic life, to help others discover what he had. This would be a lifelong concern of his.
Antioch came to suffer a three-way schism over doctrinal and disciplinary issues, and the monks wanted St. Jerome to take a side, to pick which bishop was the real one. He wrote to the Pope for advice and eventually recognized as bishop of Antioch a man named Paulinus, who ordained him a priest with a promise that he would still be able to continue his monastic life, and not have to take care of a church. 
Next, he went to Constantinople with Paulinus and St. Epiphanius to seek recognition for Paulinus from the Council of 381 and from the Emperor. They failed in this intent, but there he made friends with the bishop, St. Gregory Nazianzus, under whom he studied scripture. In 382, St. Jerome went to Rome to seek the Pope's support for Paulinus, together with the bishop and St. Epiphanius, and this time they succeeded.
By now, St. Jerome had translated into Latin Origen's homilies on Isaiah, Jeremiah, and Ezekiel, and had done other work besides. Pope St. Damasus, knowing the saint's reputation as an ascetic and his competence as a scholar, made him his secretary. The liturgy in Rome was shifting from Greek to Latin, and a better translation of the Bible was needed. So St. Jerome began revising the Latin version of the Gospels. Thus began the long project of the Vulgate, the official translation of the Latin Church.
In the few years that he spent in Rome, he made both dear friends and bitter enemies. Some of the clergy were very unhappy about the saint's criticism of what he saw as their laxity. Powerful families were unhappy he had convinced many of their daughters to become nuns instead of marrying. When the pope died, he lost his protector, and it was time to get out of town.
So in 385, St. Jerome went on a pilgrimage, first to the Holy Land and then to the desert of Netria in Egypt to see the monks. The following year he came to Bethlehem, where he would spend the rest of his life. One of his dear friends from Rome was Paula, a widowed Roman noblewoman who had accompanied him on much of his pilgrimage together with her daughter Eustochium. Paula paid for the construction at Bethlehem of a hospice for pilgrims to the Holy Land and two monasteries, one for men and one for women. Then she and her daughter moved into the monastery for women, while St. Jerome lived in a cave near the Grotto of the Nativity.
St. Jerome addressed many of his scripture commentaries and other works as well to one or both of these women. In his commentaries, he sought to bring the best exegesis of Greek and Hebrew authors to a Latin-speaking audience. Into Eustochium he had also addressed Letter 22, which is perhaps his greatest classic on the spiritual life, Letter 22.
Bethlehem was about a three-day trip from Caesarea. There was an excellent library there for biblical studies. It included something unique, Origen's Hexapla, which compared the Hebrew with the Septuagint and other Greek translations in parallel columns. St. Jerome originally used it to revise the Latin translations of the Old Testament books from the Septuagint, continuing his Bible translation project. It was ideal for this purpose because it was a very high-quality copy of the text. 
But as he did so, the parallel columns kept reminding him how the text he was translating differed from the Hebrew. So he eventually decided to undertake a new Latin translation directly from Hebrew. These translations formed most of what became known as the Vulgate, or common Latin translation of the Bible.
In the over 30 years that he spent at Bethlehem, he did many other things as well. He vigorously combated various heresies, exhorted monks to perfection, preached sermons, taught classical and Christian culture to young students, and welcomed pilgrims to the Holy Land. His last battle was against the Pelagians, who are known for saying that we can save ourselves by our own effort, without the need for God's grace.
Pelagius arrived in Jerusalem in 414, when the orthodoxy of his position was already being debated. And so the debate came to Jerusalem, and in 416, a council at Jerusalem found Pelagius orthodox. In response, St. Jerome composed Against the Pelagians to refute this. His supporters avenged themselves by attacking his monastery. They killed a deacon and set part of the building on fire, but St. Jerome saved himself by taking refuge in a strong tower. 
He was already an old man by this time, and he died in his cell a few years later, on September 30th of 419 or 420. 
Besides his many scripture commentaries, he left us several ascetic works, in addition to the translation of other works written in Greek. Personally convinced of the value of monastic life, he sought to win others into this ideal of Christian life. He challenges us to serve Christ wholeheartedly.
Praised be Jesus Christ, now and forever.