Receiving that increases the flow

בפסוק ויתן לך יתן ויחזור ויתן כו'.

On the pasuk: "And may He give you" (Bereishis 27:28) — He gives, and gives again, and gives [yet more].

The Sefas Emes opens with Chazal's reading of Yitzchak's blessing to Yaakov, where the wording implies a giving that continually renews itself.

הענין הוא כי אלה הברכות הם שיהיו בנ"י כלים לקבל את השפע הבאה מן השמים ושעי"ז יהי' נפתח מקור השפע.

The matter is that these brachos are that Bnei Yisrael should be vessels to receive the shefa (divine flow) that comes from Heaven, and that through this the source of the shefa will be opened.

The blessing's essence is to make Yisrael into fitting keilim (vessels), for the proper readiness of the receiver is what unstops the heavenly source of abundance.

כי הכל תלוי בהמקבלים אם הם כראוי כתיב והריקותי לכם ברכה כו' כאדם המריק מכלי אל כלי.

For everything depends on the receivers, whether they are fit — as it is written, "I will pour out for you a blessing" (Malachi 3:10), like a person who empties from one vessel into another.

The flow of blessing works like pouring from vessel to vessel; whether it comes depends entirely on the readiness of the one meant to receive it.

כי השי"ת עשה מדריגות זו על זו.

For Hashem made levels arranged one above the other.

Creation is structured as a chain of descending tiers.

וכולם משפיעין ומקבלין זה מזה.

And all of them give and receive from one another.

Each level both draws shefa from above it and channels shefa to the level below, forming a continuous chain of bestowal.

וכטבע הבאר ומעין כל מה שדולין ממנו יותר. נובע תמיד.

And like the nature of a well and a spring — the more one draws from it, the more it flows continually.

A living spring is not depleted by drawing; on the contrary, drawing from it causes it to well up all the more.

וכן מצינו גם בתחתונים כל מזונותיו של אדם קצובות לו מר"ה חוץ מהוצאות שבתות ויו"ט והוצאת בניו לת"ת.

And so we find also in the lower world: all of a person's sustenance is allotted to him from Rosh Hashanah, except for the expenditures of Shabbosos and Yamim Tovim and the expense of [educating] his children in Torah study.

Chazal teach that a person's annual income is fixed on Rosh Hashanah, but spending on Shabbos, Yom Tov, and Torah education is exempt from that fixed limit.

הרי יש הוצאות שמוסיפין הכנסה.

Thus there are expenditures that increase one's income.

Spending on these holy purposes actually draws down more, rather than diminishing what one has.

וכמו כן בכלל. שיש שפע היורדת בקצבה ומדה.

And likewise in general: there is shefa that descends by a fixed allotment and measure.

In the broader picture, some divine flow comes in limited, measured portions.

אבל לבנ"י הוא כמעין הנובע.

But for Bnei Yisrael it is like a welling spring.

For Yisrael, who are fitting vessels, the flow is not capped but bubbles up endlessly like a living spring.

ועל זה כתיב שתה מים מבורך.

And concerning this it is written: "Drink water from your own cistern (bor)" (Mishlei 5:15).

The pasuk distinguishes between two sources of water, hinting at two modes of receiving shefa.

בור הוא מים שנתאספו במדה.

A "bor" (cistern) is water that has been gathered in a fixed measure.

A cistern holds only the limited, collected water — the measured shefa.

וזהו בימי המעשה.

And this corresponds to the weekdays.

The measured, allotted flow belongs to the realm of the six working days.

ונוזלים מתוך בארך הוא השפע שאינו במדה והוא בחי' השבת.

And "flowing waters from within your well (be'er)" is the shefa that is not by measure, and it is the aspect of Shabbos.

The "be'er," a living wellspring, represents the unlimited flow — the boundless blessing of Shabbos, beyond all fixed allotment.

וזהו יתן ויחזור ויתן.

And this is "He gives, and gives again, and gives [more]."

The repeated giving in Yitzchak's blessing expresses this self-renewing, ever-increasing flow of the wellspring.

פי' שהקבלה תגרום התרבות השפע יותר ויותר כמעין הנובע יותר כששואבין ממנו:

The meaning is that the receiving itself causes the shefa to increase more and more, like a spring that wells up all the more when one draws from it.

Properly receiving and using the blessing does not exhaust it but multiplies it, just as drawing from a living spring only makes it flow more abundantly.

Summary: Yitzchak's blessing "He gives and gives again" teaches that the flow of divine shefa depends on the readiness of the receiver: when Bnei Yisrael make themselves fit vessels, they open the very source above. Some shefa descends in a fixed measure — like the "bor" (cistern) of the weekdays and one's allotted income — but for Yisrael it can become a living "be'er," a welling spring that, like Shabbos and like spending on Shabbos, Yom Tov, and Torah education, increases the more it is drawn upon. Receiving rightly does not deplete the blessing but causes it to multiply ever more.