“When you build a new house, you shall make a protective structure for your roof, so that you shall not put blood in your house when the one who falls from it falls. Do not plant different species [together]” (D’varim 22:8-9). Rashi (22:8) tells us that the series of commandments within which these are taught were taught together because of the concept of “mitzvah goreres mitzvah,” doing one mitzvah will lead to (the opportunity) to do another mitzvah. If one fulfills the mitzvah of “shiluach ha-kan” (sending away a mother bird before taking her offspring), which was taught immediately before these verses, he will have the opportunity to build a guardrail around the roof of a new house (i.e. he will become a homeowner). This in turn will lead to becoming a landowner, which presents the opportunity of planting crops without creating any forbidden mixtures.
Nevertheless, the way the verses are broken up into paragraphs indicates that the commandments to build a guardrail and not to plant forbidden mixtures have an even closer connection than that. After all, they are contained in the same paragraph (constituting the entire paragraph), while other mitzvos taught in bunches each have their own paragraph (even if there is a reason why these paragraphs are adjacent to each other). For example, the mitzvah of “shiluach ha-kan” (22:6-7) is contained in its own paragraph. So is the mitzvah of putting fringes on four-cornered garments (22:12), despite its following immediately after the prohibition of wearing wool and linen together (22:11) in order to teach us that these two are the preferred materials for the garment (see Shulchan Aruch Orach Chaim 9:1) and for the fringes themselves (ibid 9:2-3), as well as teaching us that fulfilling a positive commandment (wearing “tzitzis”) overrides a concurrent prohibition (wearing wool and linen together). The mitzvah of planting forbidden mixtures together is not even in the same paragraph as the two other forbidden mixtures that follow it (22:10-11). Why would the Torah group the prohibition against planting forbidden mixtures with the requirement to put a fence around a roof rather than with the other forbidden mixtures? What additional connection is there between this forbidden mixture and taking safety precautions?
The Chinuch (Mitzvah #546) explains the necessity of avoiding dangerous situations even though the Creator is in complete control: “Although G-d, blessed is He, supervises human details and knows everything that they do, and whatever happens to them, whether good or bad, is through His decree and command based on their merit or guilt… nevertheless a person must protect himself from normal occurrences because G-d created His world and built it on the foundations of the pillars (i.e. laws) of nature, and decreed that fire burns and water extinguishes the flame. Similarly, [the laws of] nature demand that if a large rock falls on a person’s head that it crushes [it], or if someone falls from a high roof to the ground that he dies. And He, blessed is He, graciously provided the human body by blowing into it a living soul with the ability to think and protect the body from whatever might happen [to it]… And since G-d made the human body subject to [the laws of] nature — as His wisdom required, being that it (the human body) is of a physical nature — He commanded him (the human) to protect [himself] from [these] occurrences. For nature, which he (the human) is given over to, will do to him whatever its laws demand if he does not protect himself from it.” In other words, if the homeowner does not build a guardrail, G-d will not (necessarily) intervene to miraculously save someone from falling off the roof. Or, as Abarbanel puts it (quoting Akeidas Yitzchok), “the guardrail will help someone who would have [otherwise] fallen, [i.e.] without there being any specific divine intention [for him to fall].” This is also what the Talmud seems to mean when it says (Bava Basra 144b) “everything [that happens to a person] is in the hands of heaven except for cold and heat” (i.e. getting sick); as Tosfos explains (d”h Hakol), “the effects (of the cold) are not the results of a decree, meaning that they could have been prevented” (i.e. by wearing a coat).
That being the case, one might think that, since we must take matters into our own hands in order to prevent the laws of nature from inflicting damage, perhaps these laws aren’t so perfect after all, or, at the very least, can be adjusted when there is reason to. If I can (and should) affect nature to the extent of interfering with what would otherwise happen, i.e. building a guardrail to stop the law of gravity from pulling someone to the ground, or wearing a coat so as not to catch a cold, maybe I should try and improve upon nature as well. But the Chinuch tells us otherwise:
“For G-d, blessed is He, created His world with wisdom, understanding and knowledge, and made and formed all things that were formed according to what each needed, appropriate to be set up that way forever; blessed is He that knows. And this is what is meant when the verse about creation says, ‘And G-d saw all that He made and behold it was very good’ (B’raishis 1:31)… And since G-d knows that all that He made was set up perfectly for its intended purpose in this world, He commanded every species to produce fruits/offspring according to its own species, as it says in the [Torah’s narrative of the] order of creation, and species should not combine with each other, so that they do not lose any bit of their perfection.”
Where does the Chinuch say this? In Mitzvah #244, explaining why there are forbidden mixtures. As he continues, “We are therefore prevented from mating different species of animals, and also warned against combining different plants and [different] trees.” (See also Mitzvah #62, where he explains that the problem with sorcerers is that they try to abuse G-d’s creation by changing things from their intended uses, including combining things in a forbidden manner.) Ramban (Vayikra 19:19) writes a similar explanation for the prohibition against these mixtures: “For G-d created for all living creatures, [whether] plant life [or] animal life, the [different] species in the world, giving them the ability to reproduce so that they can exist forever, for as long as He, may He be blessed, wants the world to continue. And He commanded (i.e. set up their nature) that they should bring out their own species (offspring just like them), not to change forever, as it says (B’raishis 1:12, 21 and 24/25) ‘according to their species.’ …And one who grafts together two species changes and goes against the act of creation, as if thinking that G-d didn’t finish His job completely.” Preventing adverse natural consequences while operating within the laws of nature is appropriate (and necessary); changing nature in order to “improve” it is not.
It is therefore possible that the Torah put these two mitzvos together, in the same paragraph, precisely because one teaches us that we should do what we can within the laws of nature to prevent its unfavorable effects, while the other teaches us that we should not try to change nature itself. This contrast becomes more obvious with these two otherwise dissimilar mitzvos paired together, separated from other mitzvos, including from those taught right before and right after them, by giving them their own paragraph.
