פירוש על דברים 22:8

כי תבנה בית חדש WHEN THOU BUILDEST A NEW HOUSE, [THEN THOU SHALT MAKE A BATTLEMENT FOR THY ROOF] — If thou hast fulfilled the command of שלוח הקן (of letting a mother bird go when the nest is rifled), you will in the end be privileged to build a new house and to fulfill the command of “making a guard-rail”, for one good deed brings another good deed in its train, and you will attain to a vineyard (v. 9), fields (v. 10) and fine garments (vv. 11—12). It is for this reason (to suggest this) that these sections are put in juxtaposition (Midrash Tanchuma, Ki Teitzei 1).

THEN THOU SHALT MAKE A PARAPET FOR THY ROOF. The commandment of the parapet is newly-declared, or it may be explanatory of the prohibition, Neither shalt thou stand idly by the blood of thy neighbor.¹⁸⁰Leviticus 19:16. But the commandment concerning mixed seeds¹⁸¹Verse 9. is explanatory, for He has already stated, Thou shalt not sow thy field with two kinds of seed.¹⁸²Leviticus 19:19. Now, this [prohibition] implied any place where they are sown; here he added that if a vineyard be sown with mixed seeds that which has been sown ‘tikdash’ (will be forfeited) together with the increase of the vineyard,¹⁸¹Verse 9. meaning to say that any benefit is forbidden just like hekdeish [“holy things” belonging to the Sanctuary from which we are prohibited to derive any benefit]. The meaning of ‘pen tikdash’ (‘lest’ thou forfeit) is like ki tikdash (“for” you shall forfeit). So also, And ye shall not go out from the door of the Tent of Meeting ‘pen tamuthu’ (‘lest’ ye die)¹⁸³Ibid., 10:7. [is like ki tamuthu — “for” you shall die]. Likewise, Neither shall ye touch it ‘pen t’muthun’ (‘lest’ ye die)¹⁸⁴Genesis 3:3. [is like ki t’muthun — “for” you shall die]. It is possible that the meaning of pen tikdash is similar to ‘pen’ their adversaries should misdeem, ‘pen’ they should say, Our hand is exalted¹⁸⁵Further, 32:27. which is like “perhaps.” The verse thus states: Do not sow the vineyard with mixed seeds, for perhaps they will sprout and the whole vineyard will be forbidden to you, for they do not become forfeit [unless they sprout] as we have been taught,¹⁸⁶Shevi’ith 7:7. “A grain crop [sown near a vine] is rendered forfeit after it has struck root, and grapes, after they have grown to the size of a white bean.”

ולא תשים דמים בביתך כי יפול הנופל, if it were to happen that someone falls off that roof you could not have been the indirect cause, seeing you had put up a protective railing. Had you not done so, your family might bear part of the guilt for such a mishap.