Wisdom as remembering the soul's root

בפסוק ואברהם זקן בא בימים אחז"ל זקן זה שקנה חכמה.

On the verse "And Avraham was old, advanced in days" (Bereishis 24:1), Chazal said: "zaken (old)" refers to one who has acquired wisdom.

The Sefas Emes opens with the Chazal that reads "zaken" as a contraction of "zeh shekanah chochmah" — one who has acquired chochmah.

דכתיב החכם עיניו בראשו.

As it is written, "The wise man — his eyes are in his head" (Koheles 2:14).

The pasuk hints that the wise person's gaze is directed to his "head" — his source.

פירוש בשורשו למעלה.

The meaning is: at his root above.

"His head" refers to his spiritual root on high, the place from which the neshamah descends.

דזה עיקר החכמה שצריך האדם להבין מאין בא ולמה בא לעוה"ז שהנשמה נשתלחה בעוה"ז מעולם העליון.

For this is the essence of wisdom — that a person must understand from where he came and why he came to this world, for the neshamah was sent into this world from the upper world.

True chochmah is the awareness that one's soul is a shaliach (emissary) dispatched from the higher world for a purpose in olam hazeh.

וע"י החכמה זוכר האדם מקומו דימים הקדמונים קודם שבא לעוה"ז.

And through wisdom a person remembers his place from the ancient days, before he came to this world.

Chochmah awakens the memory of the soul's origin, its "place" prior to entering the body.

ולכן נקרא זקן.

Therefore he is called "zaken."

One who has acquired this wisdom and remembers his root earns the title zaken.

ופי' בא בימים בפנימיות הימים דכתיב ויקרא אלקים לאור יום.

And the meaning of "advanced in days (ba bayamim)" is: he entered into the inner dimension of the days, as it is written, "And Hashem called the light 'day'" (Bereishis 1:5).

"Coming into the days" means penetrating to the penimiyus, the inner light hidden within time, for the very name "day" was given to light.

א"כ כל יום יש בו אור.

If so, every day contains light.

Since "day" was named for light, every single day holds within it a hidden ohr.

אבל גנזו לצדיקים.

But He concealed it for the tzaddikim.

This inner light is the ohr haganuz, hidden away to be revealed to the righteous.

והצדיק בא בפנימיות הימים:

And the tzaddik comes into the inner dimension of the days.

Avraham, the tzaddik, "came into the days" by reaching the concealed inner light within time itself.

Summary: To be a "zaken" is to acquire the wisdom of remembering one's source — that the neshamah is sent from the upper world for a purpose. Avraham "came into the days" means he penetrated to the penimiyus, the hidden inner light concealed within every day for the tzaddikim.