Olam shanah nefesh hinge on man

במשנה אם אין אני לי מי לי וכשאני לעצמי מה אני וא"ל עכשיו אימתי.

In the Mishnah (Avos 1:14): "If I am not for myself, who will be for me? And when I am for myself, what am I? And if not now, when?"

The Sefas Emes brings Hillel's well-known three-part teaching as the basis for his exposition.

פי' מו"ז ז"ל ידוע.

The explanation of my grandfather, of blessed memory, is well known.

He notes that his grandfather (the Chiddushei HaRim) already gave a known interpretation of this Mishnah, which he now builds upon.

וי"ל עוד כי ידוע שיש ג' בחי' עולם שנה נפש.

And one may add further, for it is known that there are three dimensions: olam (space/world), shanah (time/year), and nefesh (soul).

He invokes the classic framework (from Sefer Yetzirah) that all of reality is structured along three axes — world, time, and soul.

שהוא ענין נפש האדם.

Which is the matter of: the soul of man.

Nefesh corresponds to the human being himself — his own soul.

וכלל הבריאה.

And the totality of creation.

Olam corresponds to the entire created world.

והזמן.

And time.

Shanah corresponds to the dimension of time.

והכל תלוי בתיקון נפש האדם [*שעי"ז] הכל מתוקנים.

And everything depends on the tikkun (rectification) of man's soul, for through this all of them are rectified.

The soul is the linchpin: when a person rectifies himself, he simultaneously rectifies the world and time as well.

וז"ש אם אין אני לי לתקן נפשי.

This is the meaning of "If I am not for myself" — to rectify my own soul.

"If I am not for myself" refers to the first task: a person must work on rectifying his own nefesh.

וכשאני לעצמי כו' כי לא די בזה וצריך (גם) הוא לתקן [*גם] כל הבריאה.

"And when I am for myself…" — for this alone is not enough; he must also rectify all of creation.

"When I am only for myself, what am I?" — focusing on oneself alone is insufficient; one's avodah must extend outward to rectify the whole world (olam).

וגם הזמן ניתקן ע"י.

And time, too, is rectified through him.

Beyond self and world, the dimension of time itself becomes rectified through the person's avodah.

לכן אם לא עכשיו אימתי כי גם שעה זו צריך לתקן והיא עוברת.

Therefore "if not now, when?" — for this very hour, too, must be rectified, and it is passing.

"If not now, when?" addresses shanah/time: each passing moment also needs to be elevated, and once it slips away it is gone forever.

לכן כשיחשוב האדם שכל ג' הדברים האלו הם תלוין בו לא יתרשל בעבודת הבורא כנ"ל:

Therefore, when a person reflects that all three of these things depend on him, he will not be lax in the service of the Creator, as above.

Realizing that his soul, the entire world, and even time itself all hinge on his avodah, a person will rouse himself and never grow slack in serving Hashem.

Summary: Hillel's three statements map onto the three dimensions of reality — nefesh, olam, and shanah. "If I am not for myself" is rectifying one's own soul; "when I am for myself, what am I?" is reaching beyond oneself to rectify all of creation; "if not now, when?" is rectifying time, since each passing moment must be elevated before it is lost. Recognizing that all three depend on him, a person will never be lax in his avodah.