Musar for Ecclesiastes 12:1

It therefore is incumbent on every person to strengthen himself now in the knowledge of Torah and the fulfillment of its mitzvot, because once Moshiach comes, those years will become undesirable, as scripture states,³⁴Ecclesiastes 12:1 “Remember your Creator in the days of your youth, before the bad days come and years arrive about which you will say, ‘I have no desire in them.’” Our sages, of blessed memory said, “This refers to the days of Moshiach, in which there will neither be merit nor demerit, the reason being that the evil inclination-Yetzer HaRa will have then been abrogated.

The ninth [reason] is that during the days of his old age - with the absence of the power of emotion - he does not have the reserve of strength to create new paths in his heart, to arrange thoughts with which to fight his impulse, to attain virtues and to toil and strive in Torah and in [his] actions (and in the worlds). As it is written (Ecclesiastes 12:1), "So remember your Creator in the days of your youth, before those days of sorrow come and those years arrive of which you will say, 'I have no pleasure in them.'" Therefore, it is appropriate for a person to rush to save his soul, like the matter that is stated (Psalms 119:60), "I have rushed and not delayed to keep Your commandments."

YOUNG MAN- It is written- (Ecclesiastes 12:1) "Remember your creator in the days of your youth" For then is the ideal to serve your creator, for it is when a man has [ideal] might and strength to [give for] the Torah, to labor with all his strength on the deliberation [of the Torah] and to make ones nights like days, [maintaining only] minimal sleep. Then (i.e. his youth) he will be free, with no burdens. His consciousness will be clear and settled, able to understand, discern, listen, learn, and teach. Since he has no preoccupations, especially if he is relying on his "father's table"- [meaning] a complete lack of preoccupations, whatever he learns will be "indented" in his brain. As the saying of the sages (Ethics of the Fathers 4: 20) "One who learns in his childhood to what is he comparable? To ink written on fresh parchment, clear and sustaining". This is the Torah that remains (lit. stands) with Torah Scholars in their old age when their consciousness is settled. For Torah [learned] in youth is the "yeast in the dough", the foundation stone.