Gargantua's admonishment of Pantagruel to employ his youth to profit both in studies and in virtue:

I intend, and will have it so, that thou learn the languages perfectly; first of all the Greek, as Quintilian will have it; secondly, the Latin; and then the Hebrew, for the Holy Scripture sake; and then the Chaldee and Arabic likewise, and that thou frame thy style in Greek in imitation of Plato, and for the Latin after Cicero. Let there be no history which thou shalt not have ready in thy memory; unto the prosecuting of which design, books of cosmography will be very conducible and help thee much. Of the liberal arts of geometry, arithmetic, and music, I gave thee some taste when thou wert yet little, and not above five or six years old. Proceed further in them, and learn the remainder if thou canst. As for astronomy, study all the rules thereof. Let pass, nevertheless, the divining and judicial astrology, and the art of Lullius, as being nothing else but plain abuses and vanities. As for the civil law, of that I would have thee to know the texts by heart, and then to confer them with philosophy.

Now, in matter of the knowledge of the works of nature, I would have thee to study that exactly, and that so there be no sea, river, nor fountain, of which thou dost not know the fishes; all the fowls of the air; all the several kinds of shrubs and trees, whether in forests or orchards; all the sorts of herbs and flowers that grow upon the ground; all the various metals that are hid within the bowels of the earth; together with all the diversity of precious stones that are to be seen in the orient and south parts of the world. Let nothing of all these be hidden from thee. Then fail not most carefully to peruse the books of the Greek, Arabian, and Latin physicians, not despising the Talmudists and Cabalists; and by frequent anatomies get thee the perfect knowledge of the other world, called the microcosm, which is man. And at some hours of the day apply thy mind to the study of the Holy Scriptures; first in Greek, the New Testament, with the Epistles of the Apostles; and then the Old Testament in Hebrew. In brief, let me see thee an abyss and bottomless pit of knowledge; for from henceforward, as thou growest great and becomest a man, thou must part from this tranquillity and rest of study, thou must learn chivalry, warfare, and the exercises of the field, the better thereby to defend my house and our friends, and to succour and protect them at all their needs against the invasion and assaults of evildoers.

Furthermore, I will that very shortly thou try how much thou hast profited, which thou canst not better do than by maintaining publicly theses and conclusions in all arts against all persons whatsoever, and by haunting the company of learned men, both at Paris and otherwhere. But because, as the wise man Solomon saith, Wisdom entereth not into a malicious mind, and that knowledge without conscience is but the ruin of the soul [...]. Suspect the abuses of the world. Set not thy heart upon vanity, for this life is transitory, [...]. Be serviceable to all thy neighbours, and love them as thyself. Reverence thy preceptors: shun the conversation of those whom thou desirest not to resemble, and receive not in vain the graces which God hath bestowed upon thee. And, when thou shalt see that thou hast attained to all the knowledge that is to be acquired in that part, return unto me, that I may see thee and give thee my blessing before I die.

-- Chapter 2.VIII. in Project Gutenberg's Gargantua and Pantagruel, Complete, by Francois Rabelais written in 1532-1564, translated in 1894, see also Wikipedia on Gargantua and Pantagruel

Note that this is not advice for everyone but apparently for a very capable youth:

Pantagruel studied very hard, as you may well conceive, and profited accordingly; for he had an excellent understanding and notable wit, together with a capacity in memory equal to the measure of twelve oil budgets or butts of olives.