Midrasz do Sędziów 5:26

At Thy rebuke they fled (ibid.). When a man sees that his winepress is filled with grapes, and that his vineyard is ready for cutting, others may ask him: “What will you do with these grapes, since the vat is too small to contain them?” What does he do? He treads down the grapes in the vat and then puts in the new grapes. Then it is able to contain all his grapes. Similarly, though the entire world was submerged under water, the Holy One, blessed be He, declared: Let the dry earth appear (Gen. 1:9). The water thereupon cried out: “Though we fill the entire world, it is cramped for us. Whither shall we go?” What did the Holy One, blessed be He, do? He trampled upon the ocean⁴Normally the Mediterranean, but in this instance, as indicated a few lines below, the Dead Sea. and slew its prince,⁵See Ginzberg, Legends of the Jews 5:26, Bava Batra 74b Leviathan was a legendary sea animal destined to be eaten by the righteous in the future. as it is said: He stirreth up the sea with His power, and by His understanding he smiteth through Rahab (Job 26:12). Smiteth is an expression that indicates slaying, as it is said: And with the hammer she smote Sisera, she smote through his head, yea, she pierced and struck through his temple (Judg. 5:26). The seas mourn (bohin) to this very day because He slew the prince of the sea, as is said: Hast thou entered into the springs (nibhe) of the sea? (Job 38:16). Why did He slay him? Because a house that can accommodate a hundred living people can contain a thousand dead. That is why the ocean is called the Dead Sea. Ultimately, however, the Holy One, blessed be He, will heal it, as it is said: When they shall enter into the sea of the putrid waters, the waters shall be healed (Ezek. 47:8). When the other waters observed that the Holy One, blessed be He, had trampled upon the ocean, they fled from the loud cries of their fellow-waters, as it is said: At Thy rebuke they fled, at the voice of Thy thunder they hastened away (Ps. 104:7).

"upon your hand": This is the left hand. You say this, but perhaps it is the right? Though there is no proof for this, it is intimated in (Isaiah 48:3) "My hand has also founded on earth, and My right hand has spanned the heavens," and (Judges 5:26) "Her hand reached for the tent pin, her right for the workmen's hammer," indicating that "hand," unqualified, is the left hand. R. Yonathan says (Devarim 6:8-9) "and you shall tie them … and you shall write them": Just as the writing (of the mezuzah) is with the right hand, so, the tying of the tefillin (on the left hand). Abba Yossi says: We find the right to be called "hand," and even though there is no proof (for its application here), it is intimated in (Genesis 48:17) "that his father placed his right hand." And what is the intent of "upon your hand"? To include an amputee (of the left hand), that his tefillin are placed on his right arm.

"That the Torah of the Lord be in thy mouth" -- to exclude women [from tefillin]. What is exemplary about tefillin? They are a positive time-triggered commandment from which women are exempt. So too, are women exempt from all positive time-triggered commandments.

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).

(Shemoth 13:9) "upon your hand" — the left hand, as it is written (Isaiah 48:13) "My hand also has founded the earth, and My right hand has spanned the heavens," and (Judges 5:26) "She sent forth her hand for the (tent-) peg and her right hand for the laborers' hammer," and (Psalms 74:11) "Why do You withdraw Your hand, and Your right hand, etc." — whence we see that "hand" (by itself) in all places is the left hand.