The hundred berachos open gates of bracha

בפסוק וימצא מאה שערים.

On the pasuk: "And he found a hundred-fold (literally, a hundred gates)."

Yitzchak's harvest in the year of famine is read by the Sefas Emes not only as material increase but as the opening of a hundred spiritual gateways.

הגיד אמו"ז ז"ל כי אלה המאה שערים נפתחים בכל יום בכח מאה ברכות וכ"ה בריקאנטי ע"ש.

My grandfather and teacher, of blessed memory, taught that these hundred gates are opened every day through the power of the hundred berachos (blessings), and so it is also in the Recanati — see there.

The hundred berachos a Jew recites daily are the keys that swing open these hundred gates of bracha, drawing down shefa (Divine flow) anew each day.

והנה בזה נתקיים הפסוק מה רב טובך אשר צפנת ליראיך.

Through this is fulfilled the pasuk: "How abundant is Your goodness, which You have stored away for those who fear You" (Tehillim 31:20).

The vast good Hashem holds in reserve is not lost; it is "stored away," waiting to be unlocked specifically by those who possess yiras Shomayim (awe of Heaven).

ולכן יצחק עמוד היראה נגלה לו המאה שערים כמו שדרשו חז"ל בפסוק מה ה' אלקיך שואל מעמך כי אם ליראה.

Therefore to Yitzchak, who is the pillar of yirah (awe), the hundred gates were revealed, as Chazal expounded on the pasuk: "What (mah) does Hashem your God ask of you? Only to fear Him" (Devarim 10:12).

Yitzchak embodies the middah of yirah, so he in particular merited that these hundred gates of bracha be opened to him.

ואמרו אל תקרי מה אלא מאה.

And they said: do not read it "mah" (what) but "me'ah" (a hundred).

Chazal reread the word "mah" as "me'ah," teaching that the hundred berachos are precisely what Hashem "asks of you" — and they are accessed through yirah.

כמו כן מה רב טובך הוא מאה.

Likewise, "How (mah) abundant is Your goodness" also alludes to "a hundred."

The same wordplay applies here: the "mah" of Hashem's abundant good is the hundred gates of stored-up bracha.

וגמר אומר כי אם ליראה שע"י היראה זוכין לקבל הברכות שהם צפון ליראיו.

And the pasuk concludes "only to fear," for through yirah one merits to receive the berachos that are stored away for those who fear Him.

Yirah is the condition: only one who stands in awe before Hashem becomes fit to receive the treasured bracha set aside for the yorei Shomayim.

ונמסר מפתחא דמאה ברכאין ביד האדם.

And the key of the hundred berachos has been handed into the hand of man.

Hashem entrusts the key itself to the person — the daily berachos are within human reach, so the unlocking depends on us.

כדאיתא בזוה"ק לך.

As is brought in the Zohar HaKadosh, parshas Lech Lecha.

The Sefas Emes cites the Zohar as his source that this key is placed in man's hand.

ריש הסדר.

At the beginning of the parsha.

A precise reference: the teaching appears at the very opening of that section of the Zohar.

ולכן ה' אלקיך שואל מעמך.

And this is why "Hashem your God asks of you" — it is demanded "from you," from within yourself.

The avodah is placed "me'imach," upon the person himself, because the key has been given into his hand.

כי משמים רוצין להשפיע כל הברכות תמיד רק שיהי' אדם כלי לקבל הברכות והוא בכח המאה ברכאין:

For from Heaven they always wish to pour down all the berachos; it only remains that a person make himself a vessel to receive the berachos — and that is accomplished through the power of the hundred berachos.

Hashem's flow of good is constant and never withheld from above; the entire avodah is to fashion oneself into a fitting kli (vessel), and the hundred daily berachos are the tool that prepares that vessel.

Summary: The "hundred gates" Yitzchak found are the hundred daily berachos, the keys that open Hashem's constantly flowing goodness. That goodness is "stored away for those who fear Him," so it is yiras Shomayim that makes a person into a vessel; the key has been placed in our own hands, and our task is simply to use it to receive what Heaven always wishes to give.