I. Merciful Skipping
שמ’ יב:יג – וראיתי את הדם ופסחתי עלכם.
Ex. 12:13 – I will see the blood and pass over you.
מכילתא (בא פרשה ז): וראיתי את הדם. היה ר’ ישמעאל אומר והלא הכל גלוי לפניו, שנאמר: ידע מה בחשוכא ונהורא עמיה שרא (דנ’ ב:כב), ואומר: גם חשך לא יחשיך ממך (תה’ קלט:יב), ומה ת”ל וראיתי את הדם. אלא בשכר מצוה שאתם עושים אני נגלה וחס עליכם, שנאמר: ופסחתי עליכם, אין פסיחה אלא חייס, שנאמר: כצפרים עפות כן יגן ה’ צבאות על ירושלם גנון והציל פסוח והמליט (ישע’ לא:ה). ופסחתי עליכם. ר’ יאשיה אומר אל תקרי ופסחתי אלא ופסעתי שהב”ה מדלג על בתי בני ישראל במצרים. שנאמר: קול דודי הנה זה בא מדלג על ההרים (שה”ש ב:ח).
Mechilta (Bo, Parsha 7): And I shall see the blood – Rabbi Ishmael said, is not everything revealed to Him, as it is written: in the merit of the Mitzva which you perform I will reveal Myself and spare you, as it is written: He knows what is in the dark, and light dwells with Him (Dan. 2:22), and furthermore: Even darkness will not obscure [anything] from You (Ps. 139:12); Wherefore then, “And I shall see the blood”? Rather, in the merit of of the Mitzva that you have performed I reveal Myself and pity you, as it is written: and pass over you (ופסחתי). This term denotes mercy, as it is written: Like flying birds, so shall the Lord of Hosts protect Jerusalem, protecting and saving, passing over and rescuing (Is. 35:5). And pass over you – Rabbi Josiah said, read not ופסחתי (pass over) but ופסעתי (skip over), for the Holy One, blessed be He skipped over the houses of the Israelites in Egypt. As it is written: The sound of my beloved! Behold, he is coming, skipping over the mountains (Song 2:8).
Rabbi Josiah employs the Rabbinic tool of אל תיקרי to support his exposition that פסחתי (passing over) is similar in meaning (and close linguistically) to פסעתי (skipping), and an אסמכתא (quasi-proof) from the verse in the Song of Songs, which refers to skipping, which his tradition taught him referred to the Israelite houses which were skipped over. This is, after all the common understanding of the word פסחתי.
Rabbi Ishmael’s discourse on the other hand, is somewhat puzzling. What is the practical difference between “showing mercy” on the one hand and “skipping over” on the other – is the end result not the same… the Israelites’ houses will be skipped over, i.e. spared.
And what is the purpose of quoting the verse in Isaiah; the word פסוח does not appear to add anything to our understanding of פסחתי – if both mean skipping, then why quote it? And if the point is to demonstrate that the word means “mercy” – how does this verse prove it?
Rashi paraphrases the two views from the Mechilta:
רש”י שמ’ יב:יג – ופסחתי – וחמלתי, ודומה לו: פסוח והמליט (ישע’ לא:ה). ואני אומר כל פסיחה לשון דלוג וקפיצה ופסחתי מדלג הי’ מבתי ישראל לבתי מצרים שהיו שרוים זה בתוך זה.
Rashi Ex. 12:13 – ופסחתי [is rendered] and I will have pity, and similar to it: “sparing פסוח and rescuing” (Isa. 31:5). I say, however, that every [expression of] פסיחה is an expression of skipping and jumping. [Hence,] ופסחתי [means that] He was skipping from the houses of the Israelites to the houses of the Egyptians, for they were living one in the midst of the other.
By saying “and I say”, Rashi implies that he prefers the opinion of Rabbi Josiah over that of Rabbi Ishmael (and Onkelos, usually favored by Rashi). What is it that troubles Rashi about this opinion?
It must first be said that we English speakers are automatically prejudiced to the view of Rabbi Josiah by the mere use of the term “Passover.” This name presumes that the meaning of the word פסיחה is “skipping,” as Rabbi Josiah says. However, Rashi’s comments remind us that this definition is not accepted universally, and the literal definition may be completely different.
Rabbi Ishmael is troubled first and formost by the image of Hashem (Himself, and not through an angel or messenger, as the Haggadah reminds us) “skipping” from house to house to check for evidence of blood, since there is no need whatsoever for G-d in His Omniscence to do so. Therefore Rabbi Ishmael believes that the word פסיחה may mean something different entirely. But why “mercy” specifically and how does he derive this from the verse in Isaiah?
II. Benignly Sheltering
Let’s examine the word חס, here translated as mercy. This term is actually the source of the word מחסה (refuge), as in:
תה‘ סא:ה – אחסה בסתר כנפיך.
Ps. 61:5 – I will take shelter in the cover of Your wings forever.
תה‘ ה:יב – וישמחו כל חוסי בך לעולם ירננו.
Ps. 5:12 – And let all who take refuge in You rejoice.
According to this, Rabbi Ishmael would be saying that פסיחה means refuge and shelter, a definition that indeed provides a very different understanding of the mechanism of the salvation of the Israelites on that fateful night. The conventional image is that of death skipping from house to house and passing over those houses with the blood smeared on the doorposts; this leaves the impression that the blood is somehow itself imbued with a measure of power to ward off evil. But R. Ishmael asserts that since ועברתי denotes that Hashem Himself is carrying out the deeds, the word וראיתי cannot mean seeing the blood. Rather the word וראיתי here is like the הָפעל, i.e. like הראיתבהר – I revealed myself to spare, to shelter your household.
This, then is what is learned from the verse in Isaiah; the entire context there:גנן, הציל, המליט instills an iron-clad confidence that no harm could possibly come to the city – as if it is utterly surrounded by an impenetrable spiritual forcefield, a fortified and indestructible refuge – מחסה.
III. How a Garden Grows
This is also reinforced by the etymology of the terms of salvation used in in the verse in Isaiah. Rabbi S. R. Hirsch explains the interrelationship between the root גנן and its derivatives:
רש”ר הירש בר’ ב:ח – גן בעדן – ‘גן’ משרש ‘גנן’, ומכאן: ‘הגן’. נמצא ‘גן’: מקום גדור ושמור לצורך אדם (מצינו יחס זה גם בלע”ז: “garden” מיסוד “guard”).
Rabbi S. R. Hirsch Gen. 2:8 – A garden in Eden – גן (garden) is from the root גנן, from which derivesהגן (protecting) as well. Therefore גן means: an area enclosed and guarded for the enjoyment of people (this relationship exists in other languages as well: garden from guard).
IV. Shade me, O L-rd
The next word used in the verse is הציל. According to the 10th-century grammarian Menachem Ibn Saruk, the root of הציל are the two letters צל, the same word as shade or shadow. The implication is that the type of salvation specified by הציל is not e.g. extrication or destruction of the enemy, but simple shelter from danger, in the comforting shadow of the savior.
V. From Rescuing to Cementing
The final word used in the passage in Isaiah, המליט, is usually translated as rescuing or deliverance, as in:
יר’ יח:לט – כי מלט אמלטך ובחרב לא תפל.
Jer. 18:39 – For I will surely deliver you and you shall not fall by the sword.
Many commentators point out the similarity between the two words מלט and פלט, also meaning rescuing:
תה’ יח:ג – ה’ סלעי ומצודתי ומפלטי.
Ps. 18:3 – The Lord is my rock and my fortress, and a rescuer to me.
The early 20th-century linguist, Rabbi S. J. Shteiger, suggests a link to the word שלט as well, meaning shield in the Tanach:
ש”ב ח:ז – ויקח דוד את שלטי הזהב .
II Sam. 8:7 – And David took the shields of gold.
And I humbly suggest adding the following word meaning refuge to the list:
במ’ לה:יא – ערי מקלט.
Num. 35:11 – Cities of refuge.
All of these words have two things in common: 1. the concept of protection and salvation.2. the letters לט.Indeed, we find the root לט in a similar sense as well:
מ”א יט:יג – ויהי כשמע אליהו וילט פניו באדרתו.
I Kings 19:13 And as Elijah heard, he wrapped his face in his mantle
The underlying concept of protection and salvation are actally illustrated by the seemingly unrelated noun form of the root מלט:
יר’ מג:ט – קח בידך אבנים גדלות וטמנתם במלט.
Jer. 43:9 – Take in your hand large stones and hide them in the mortar.
Mortar? Yes, mortar was used not only to hold bricks together, but to cover and protect them from the elements, or even to hide precious items when necessary to safekeeping, as here.
In short, Rabbi Ishmael looked at the context of the verse in Isaiah, and examined the context in which the word פסוח was used. Since all the other terms point to salvation though shelter, so too mustפסוח mean shelter, which he refers to as חייס, as in מחסה – refuge.
Let us pray that the Hashem’s everlasting assurance to the Jewish People and His Eternal city continue to be fulfilled, that we be sheltered and protected even as evil is purged from the earth.
במהרה בימינו אמן.
 This is also the source of the Aramaic term for prayer: צלותא .
 This is why a government is called a שלטון – its principle purpose is to shield the population from harm.