bentching and the bracha of shalom

Two weeks ago I mentioned R' Akiva Eiger's safeik (on SA OC 188) as to whether a katan who ate to the point of שׂביעה and bentched just before nightfall and then became bar mitzvah after nightfall has to repeat bentching or not.  Is the chiyuv of bentching dependent on achila, which took place while the person was a katan and so he was yotzei with his bentching as a katan, or does the chiyuv depend on שׂביעה, and since he is in a state of שׂביעה as a gadol he has to repeat bentching since he did not fulfill his mitzvah as a gadol.

 I bring it up again because of a Panim Yafos on our parsha. 

 

וְהִשִּׂ֨יג לָכֶ֥ם דַּ֙יִשׁ֙ אֶת־בָּצִ֔יר וּבָצִ֖יר יַשִּׂ֣יג אֶת־זָ֑רַע וַאֲכַלְתֶּ֤ם לַחְמְכֶם֙ לָשֹׂ֔בַע וִֽישַׁבְתֶּ֥ם לָבֶ֖טַח בְּאַרְצְכֶֽם

 

Rashi comments:

 

ואכלתם לשובע – אוכל קימעא והוא מתברך במעיו.

 

To connect this phrase with the end of the pasuk, Panim Yafos quotes the gemara in Brachos 20b:

 

דרש רב עוירא זמנין אמר לה משמיה דר' אמי וזמנין אמר לה משמיה דר' אסי אמרו מלאכי השרת לפני הקב"ה רבש"ע כתוב בתורתך אשר לא ישא פנים ולא יקח שחד והלא אתה נושא פנים לישראל דכתיב ישא ה' פניו אליך אמר להם וכי לא אשא פנים לישראל שכתבתי להם בתורה ואכלת ושבעת וברכת את ה' אלהיך והם מדקדקים [על] עצמם עד כזית ועד כביצה

 

We earn Hashem's special favor of the bracha יִשָּׂא ה' פָּנָיו אֵלֶיךָ וְיָשֵׂם לְךָ שָׁלוֹם because we go the extra mile for Hashem.  Even though the chiyuv bentching applies only when you hit the state of שׂביעה, we do more and bentch even after eating only a k'zayis or a k'beitzah.

 

If that's the case, when we are in a situation where אוכל קימעא והוא מתברך במעיו and there is שׂביעה even from eating just a little bit, a person is therefore mechuyav to bentch even on that little bit.  Doing so is not going the extra mile -- it's simply fulfilling the basic chiyuv required.  A person might think therefore that יצאת שׂכרה בּהפסדה because if we can't prove that we go the extra mile we lost the special reward of יִשָּׂא ה' פָּנָיו אֵלֶיךָ וְיָשֵׂם לְךָ שָׁלוֹם, kah mashma lan the end of the pasuk וִֽישַׁבְתֶּ֥ם לָבֶ֖טַח בְּאַרְצְכֶֽם that Hashem gurantees that we will not lose out.

 

The Panim Yafos in this shtickel Torah is taking sides in RAKE's safeik, as he assumes mi'doraysa you have to bentch so long as you are satiated, no matter how little you eat.