כֹּ֚ה אָמַ֣ר יְהוָ֔ה הִשָּׁמְר֖וּ בְּנַפְשֽׁוֹתֵיכֶ֑ם וְאַל־תִּשְׂא֤וּ מַשָּׂא֙ בְּי֣וֹם הַשַּׁבָּ֔ת וַהֲבֵאתֶ֖ם בְּשַׁעֲרֵ֥י יְרוּשָׁלִָֽם׃
אַזױ האָט גאָט געזאָגט: היט אײַך אום אײַער זעל, און איר זאָלט ניט טראָגן קײן משׂא אין טאָג פֿון שבת און אַרײַנברענגען אין די טױערן פֿון ירושָלַיִם.
Rashi
מקצר רוח THROUGH ANGUISH (lit. shortness) OF SPIRIT — If one is in anguish his breath comes in short gasps and he cannot draw long breaths. In a somewhat similar manner to this I heard this section expounded by Rabbi Baruch the son of Rabbi Eliezer, and he cited the following verse to me in proof of his explanation: (Jeremiah 16:21) “This once will I cause them to know My hand and My might, and they shall know that My Name is the Lord”. Rabbi Baruch said: we may learn from this text that when the Holy One, blessed be He, fulfils His words, even when it is a matter of punishment, He makes it known that His Name is the Lord; and, of course, this is all the more so, when He fulfils His words in a matter of bestowing reward. — Our Rabbis explained it (this section) as having reference to what precedes it — that Moses said (5:22): “Wherefore hast thou done so evil [to this people]”. Whereupon God said to him, “Alas, for those that are gone (i. e. the patriarchs) and are no more to be found! I really have reason to deplore the death of the patriarchs. Many a time did I reveal Myself to them by the name ‘God Almighty’, and not once did they ask Me, What is Thy Name? (i. e. what is the name that describes Thy true essence); but thou hast at once said (Exodus 3:13) “[If they ask] ‘what is His name’, what shall I say unto them?!” (Exodus Rabbah 6:4; Sanhedrin 111a).