Objection 2: Further, learning precedes teaching, for a man must learn from another before he teaches another. Now the Old Law contains precepts about teaching -- -both affirmative precepts as, for example, (Dt.4:9), "Thou shalt teach them to thy sons" -- -and prohibitive precepts, as, for instance, (Dt.4:2), "You shall not add to the word that I speak to you, neither shall you take away from it." Therefore it seems that man ought to have been given also some precepts directing him to learn.
Objection 3: Further, knowledge and understanding seem more necessary to a priest than to a king, wherefore it is written (Malachi 2:7): "The lips of the priest shall keep knowledge, and they shall seek the law at his mouth," and (Osee 4:6): "Because thou hast rejected knowledge, I will reject thee, that thou shalt not do the office of priesthood to Me." Now the king is commanded to learn knowledge of the Law (Dt.17:18,19). Much more therefore should the Law have commanded the priests to learn the Law.
Objection 4: Further, it is not possible while asleep to meditate on things pertaining to knowledge and understanding: moreover it is hindered by extraneous occupations. Therefore it is unfittingly commanded (Dt.6:7): "Thou shalt meditate upon them sitting in thy house, and walking on thy journey, sleeping and rising." Therefore the precepts relating to knowledge and understanding are unfittingly set down in the Law.
On the contrary, It is written (Dt.4:6): "That, hearing all these precepts, they may say, Behold a wise and understanding people."
I answer that, Three things may be considered in relation to knowledge and understanding: first, the reception thereof; secondly, the use; and thirdly, their preservation. Now the reception of knowledge or understanding, is by means of teaching and learning, and both are prescribed in the Law. For it is written (Dt.6:6): "These words which I command thee . . . shall be in thy heart." This refers to learning, since it is the duty of a disciple to apply his mind to what is said, while the words that follow -- -"and thou shalt tell them to thy children" -- -refer to teaching.
The use of knowledge and understanding is the meditation on those things which one knows or understands. In reference to this, the text goes on: "thou shalt meditate upon them sitting in thy house," etc.
Their preservation is effected by the memory, and, as regards this, the text continues -- -"and thou shalt bind them as a sign on thy hand, and they shall be and shall move between thy eyes. And thou shalt write them in the entry, and on the doors of thy house." Thus the continual remembrance of God's commandments is signified, since it is impossible for us to forget those things which are continually attracting the notice of our senses, whether by touch, as those things we hold in our hands, or by sight, as those things which are ever before our eyes, or to which we are continually returning, for instance, to the house door. Moreover it is clearly stated (Dt.4:9): "Forget not the words that thy eyes have seen and let them not go out of thy heart all the days of thy life."
We read of these things also being commanded more notably in the New Testament, both in the teaching of the Gospel and in that of the apostles.
Reply to Objection 1: According to Dt.4:6, "this is your wisdom and understanding in the sight of the nations." By this we are given to understand that the wisdom and understanding of those who believe in God consist in the precepts of the Law. Wherefore the precepts of the Law had to be given first, and afterwards men had to be led to know and understand them, and so it was not fitting that the aforesaid precepts should be placed among the precepts of the decalogue which take the first place.
Reply to Objection 2: There are also in the Law precepts relating to learning, as stated above. Nevertheless teaching was commanded more expressly than learning, because it concerned the learned, who were not under any other authority, but were immediately under the law, and to them the precepts of the Law were given. On the other hand learning concerned the people of lower degree, and these the precepts of the Law have to reach through the learned.
Reply to Objection 3: Knowledge of the Law is so closely bound up with the priestly office that being charged with the office implies being charged to know the Law: hence there was no need for special precepts to be given about the training of the priests. On the other hand, the doctrine of God's law is not so bound up with the kingly office, because a king is placed over his people in temporal matters: hence it is especially commanded that the king should be instructed by the priests about things pertaining to the law of God.
Reply to Objection 4: That precept of the Law does not mean that man should meditate on God's law of sleeping, but during sleep, i.e. that he should meditate on the law of God when he is preparing to sleep, because this leads to his having better phantasms while asleep, in so far as our movements pass from the state of vigil to the state of sleep, as the Philosopher explains (Ethic. i, 13). In like manner we are commanded to meditate on the Law in every action of ours, not that we are bound to be always actually thinking about the Law, but that we should regulate all our actions according to it.