Midrasz do Wyjścia 13:10

You find that the festivals were granted to the Israelites for their pleasure. The Holy One, blessed be He, said: “Delight yourself therein so that you may repeat them in the year to come,” as it is said: And thou shalt therefore keep this ordinance in its season from year to year (Exod. 13:10). That is to say, you should repeat them yearly. Therefore, one may say: Just as an individual blesses the Holy One, blessed be He, so does the Holy One bless him.

... This is the [first] month to you ~ The first ancestors did not count it. Is it possible that the first ancestors did not count it? Behold, the Torah was not given in their days, but from the moment Torah was given and onward, the first comers (ie, the other nations) would count. No, this is not possible: the text says - "for you". You count it [as the first month], and the other nations do not.[First of] Months - Is it possible [that this is the first month] for [beginning of] years and shemittah [cycles] and Jubilee [cycles]? [No,] the text says "first of months" - for months it is the first, but it is not the first for the [beginning of] years, nor shemittah [cycles], nor Jubilee [cycles]. "It is first for you [all]" - and not for the tenth part of animals, and not for the fruits. Why is it the first for kings and festivals and donations of shekels and documents of houses? "It is first" - because of the general principle that is said: "guard the month of Aviv". How do you guard it? Add days to it. Is it possible that, if it was a year that lacks ten or twenty days one would complete it like that [with just ten or twenty days]? [No,] the text says "month" - there is no [adding] less than a month. Is it possible that, if it was a year that lacks forty or fifty days one would complete it like that [with forty or fifty days]? [No,] the text says "month" there is no adding more than a month. Is it possible to complete the year with Nisan? [No,] the text says "it is the first month to you" - one Nissan you make, and you do not make two Nissan. Is it possible to complete the year with Tishrei? [No,] the text says "guard the month of Aviv" - guard the month that is close to Aviv [spring], and which one is it? Adar. Is it possible that if it is an early year [ie, autumn comes early] you would add days to it? And similarly if it was a late year you would take away days from it? [No,] the text says "and you will guard this rule in its appointed time from year to year" - a year is never less than twelve months. "It is the first month for you of the months of the year" - a second Nisan should not be done.

The four passages are written upon one roll of parchment and are inserted into the phylacteries that are placed on one’s arm. These four are included also in the phylactery that is placed on the forehead, but they are written on four separate slips of parchment. Whence do we know that four separate slips of parchment are necessary? From the word totafot. Tot is a Coptic word meaning “two”; and fot is an African word meaning “two,” thus making four for the head phylactery, and a total of five parchments in all. How do we know that the arm phylactery contains (only) one (parchment)? Since it is written: And it shall be for a sign upon thy hand (the word your hand is spelled with an extra heh, which has a numerical value of five) and so so there are five (parchments) in all. Hence you learn that the phylactery containing the four verses on separate pieces of parchment is placed upon the head, and the phylactery with the one parchment, containing the same four verses, is placed upon the arm. It might be possible to maintain that the phylactery with the four parchments is placed upon the arm, and so Scripture says: And it shall be for a sign upon thy hand. Where is it placed on the hand? You might maintain that it is placed on the arch of the hand just as it is placed on the arch of the head. Therefore, Scripture says: And these words, which I command thee this day, shall be upon thy heart (Deut. 6:6). From this statement they concluded: One must place the phylactery on the part of the arm opposite the heart. You might contend that the phylacteries are to be put on at night. Hence Scripture says: In its season from day to day (Exod. 13:10), namely, in the daytime and not at night. You might maintain: Perhaps they are to be donned on the Sabbath or the holy days. Therefore Scripture says: From day to day, implying that there are days on which a man dons them and days on which he does not. The days on which he does not don them are the Sabbath and the holy days. You might say: Perhaps he should place the phylacteries on his right hand. Scripture, therefore, says: Upon thy hand, and the word thy hand is used only in reference to the left hand, as it is said: Yea, My hand hath laid the foundation of the earth, and My right hand hath spread out the heavens (Isa. 48:13). Scripture likewise says; Her hand she put to the tentpin, and her right hand to the workman’s hammer (Judg. 5:26).