Here are some references to meditation on Scripture from the Letters of St. Jerome [Christian Classics Ethereal Library]:
“You write that our brother, Rufinus, has not yet come to you. Even if he does come it will do little to satisfy my longing, for I shall not now be able to see him. He is too far away to come hither, and the conditions of the lonely life that I have adopted forbid me to go to him. For I am no longer free to follow my own wishes. I entreat you, therefore, to ask him to allow you to have the commentaries of the reverend Rhetitius, bishop of Augustodunum [Autun] copied, in which he has so eloquently explained the Song of Songs. A countryman of the aforesaid brother Rufinus, the old man Paul, writes that Rufinus has his copy of Tertullian, and urgently requests that this may be returned. Next I have to ask you to get written on paper by a copyist certain books which the subjoined list will show you that I do not possess. I beg also that you will send me the explanation of the Psalms of David, and the copious work on Synods of the reverend Hilary, [Hilary of Poitiers] which I copied for him [Rufinus] at Trêves with my own hand. Such books, you know, must be the food of the Christian soul if it is to meditate in the law of the Lord day and night."
- Letter V to Florentius from the Syrian desert, ca. 374 A.D.
“What honey is sweeter than to know the wisdom of God? others, if they will, may possess riches, drink from a jewelled cup, shine in silks, and try in vain to exhaust their wealth in the most varied pleasures. Our riches are to meditate in the law of the Lord day and night [Ps. 1:2], to knock at the closed door, [Matt. 7:7], to receive the ‘three loaves’ of the Trinity, [Luke 11:5–8], and, when the Lord goes before us, to walk upon the water of the world.” [Matt. 14:25–33]."
- Letter XXX to St. Paula from Rome, 384 A.D.
“The apostle Paul learned the Law of Moses and the prophets at the feet of Gamaliel and was glad that he had done so, for armed with this spiritual armour, he was able to say boldly ‘the weapons of our warfare are not carnal, but mighty through God to the pulling down of strongholds;’ armed with these we war ‘casting down imaginations and every high thing that exalteth itself against the knowledge of God, and bringing into captivity every thought to the obedience of Christ; and being in a readiness to revenge all disobedience’ [II Cor. 10:4–6]. He writes to Timothy who had been trained in the holy writings from a child exhorting him to study them diligently [II Tim. 3:14,15] and not to neglect the gift which was given him with the laying on of the hands of the presbytery. [I Tim. 4:14]. To Titus he gives commandment that among a bishop’s other virtues (which he briefly describes) he should be careful to seek a knowledge of the scriptures: A bishop, he says, must hold fast ‘the faithful word as he hath been taught that he may be able by sound doctrine both to exhort and to convince the gainsayers.’”
- Letter LIII to Paulinus, bishop of Nola, written 394 A.D.
"Her [St. Marcella's] delight in the divine scriptures was incredible. She was for ever singing, ‘Thy words have I hid in mine heart that I might not sin against thee,’ [Ps. 119:11]. as well as the words which describe the perfect man, ‘his delight is in the law of the Lord; and in his law doth he meditate day and night.’ [Ps. 1:2]. This meditation in the law she understood not of a review of the written words as among the Jews the Pharisees think, but of action according to that saying of the apostle, “whether, therefore, ye eat or drink or what soever ye do, do all to the glory of God.” [1 Cor. 10:31]. She remembered also the prophet’s words, ‘through thy precepts I get understanding,’ [Ps. 119:104], and felt sure that only when she had fulfilled these would she be permitted to understand the scriptures. In this sense we read elsewhere that ‘Jesus began both to do and teach.’ [Acts 1:1]. For teaching is put to the blush when a man’s conscience rebukes him; and it is in vain that his tongue preaches poverty or teaches alms-giving if he is rolling in the riches of Crœsus and if, in spite of his threadbare cloak, he has silken robes at home to save from the moth.”
- Letter CXXVII to St. Principia as a memoir of the death of St. Marcella, written from Bethlehem, 412 A.D.
“She [Demetrius, a high born lady of Rome] was filled with admiration for the manner of life followed by Elijah and by John the Baptist; both of whom confined and mortified their loins with girdles of skin, [II Kings 1:8; Matt. 3:4], while the second of them is said to have come in the spirit and power of Elijah as the forerunner of the Lord [Matt. 11:14; Luke 1:17]. As such he prophesied while still in his mother’s womb, [Luke 1:41] and before the day of judgment won the commendation of the Judge [Matt. 11:7–14]. She admired also the zeal of Anna the daughter of Phanuel, who continued even to extreme old age to serve the Lord in the temple with prayers and fastings. [Luke 2:36, 37]. When she thought of the four virgins who were the daughters of Philip, [Acts 21:9] she longed to join their band and to be numbered with those who by their virginal purity have attained the grace of prophecy. With these and similar meditations she fed her mind, dreading nothing so much as to offend her grandmother and her mother.”
- Letter CXXX to Demetrius, written in 414 A.D,