In plain words
When the students had studied under their gurus, completed their learning, and were about to enter the householder's āśrama, the teachers drew the children close and gave them message and counsel on what kind of life they should lead in future: this is the Taittirīya Upaniṣad. In it there is one called the preyomārga, and another called the śreyomārga. The preyomārga is merely the fruit of the senses, which gives joy for the moment. These are passing pleasures. These are impermanent and untrue. Many people keep wishing for this very preyomārga. But the śreyomārga, lasting and true, many do not wish for. The reason is this: they take some time, though. Man will not agree to wait so long for the result. Man's speed in everything is very great. Man runs at everything. Among the hopes he hopes, he keeps in view only those that suit him. He keeps wanting good positions, a good name, good standing, a good life. But he does not wish for good knowledge, good conduct, good understanding. What gives good qualities, good conduct, good behaviour and good knowledge is the śreyomārga itself. What wishes for positions, honours and fame for the moment is the preyomārga. The teachers called the children: Students! What is the supreme goal of education? The supreme goal of education is humility itself. Modesty itself is the chief aim. Character itself is the chief life-breath. Teaching the children all these, giving it the name Śikṣāvallī, it goes on teaching that in future, on the householder's path, you must follow it in lasting Dharma and on the path of Satya.
‘Mātṛdevo bhava’, ‘pitṛdevo bhava’. First of all, honour your mother and father. In no circumstances must you let go of Satya. You must not stray from Dharma in the least. By teachings of this kind it filled the hearts of the students of that day with full contentment, set them on the good path, and was able to turn humanness into divinity. All the learning of today keeps turning humanness into the demonic and the bestial. Today's learning develops only cleverness, and does not develop good qualities at all. They show no gratitude; instead they are turning out ungrateful. This is a path contrary to education.