Yesterday, we noted the explanation given by the Gemara (Bava Metzia 61b) for why the Torah in Parashat Shelach concludes its discussion of tzitzit by recalling the event of the Exodus. The Gemara, as cited by Rashi, explains: “I am the One who distinguished in Egypt between the drop [that produced] a firstborn and the drop [that produced a child] who was not a firstborn, and I will, in the future, distinguish and punish one who affixes kala ilan to his garment and says it is tekehelet.” People were tempted to save the expense of purchasing tekhelet – the special dye required for one of the tzitzit strings – by using instead the outwardly similar, but much less expensive, kala ilan dye. God warns such people that just as He was able to identify the firstborns in Egypt, even those who were conceived out of wedlock and thus did not know they were firstborns, he can also distinguish between genuine tekhelet and a counterfeit product.
Rav Shimon Moshe Diskin, in his Mas’at Ha-melekh, suggests an explanation for the connection drawn by the Gemara between counterfeit tekhelet and the plague of the firstborn. He notes that several verses earlier (15:39), the Torah explains the mitzva of tzitzit as intended to remind us of the mitzvot: “…you will see it and remember all the commandments of the Lord and perform them.” The Sifrei explains that the color of the tekhelet dye resembles the color of the sky, and thus viewing the tekhelet will remind us of our obligations to God. One might therefore have justified the practice of substituting tekhelet with a cheaper imitation, since both would have the same effect. As kala ilan outwardly resembles tekhelet, it would seem not to make any difference which material one uses as a reminder on his garment of God’s Heavenly Throne.
The Gemara therefore draws our attention to the plague of the firstborn, to the night when God once and for all forced Pharaoh to release Benei Yisrael by striking the firstborn children in his kingdom. On the surface, this result would have been achieved regardless of whether God had ensured to kill all biological firstborns and to spare the others. Pharaoh would, in all likelihood, have been no less shaken by the catastrophe that struck his kingdom if God had killed the presumed firstborns in each household, rather than kill only the true biological firstborns. Nevertheless, for reasons we can only speculate, God determined it was necessary to kill only those who were their biological fathers’ first children. The Gemara teaches that just as our limited human minds are incapable of understanding this decision, we similarly cannot assume to know the reasons behind all the Torah’s laws, such that we could make modifications which we deem appropriate. We cannot substitute tekhelet with kala ilan because God commanded us to use tekhelet, even if we think kala ilan could achieve the same desired effect, and this sense of humble, unquestioning submission must characterize our approach to all the Torah’s laws.