Musar for Menachot 58:5

The meaning of מתחלה עלה במחשבה לברא את העולם במדת הדין, does not mean that G–d thought something at the beginning, and then changed His mind, G–d forbid; it means that G–d was concerned with the root of things, the שורש. The root is the "beginning," from which all other developments evolve. The root is in a domain concealed from us, נעלם. It is the beginning of any further expansion. Things become visible from that point on. G–d was able to apply the מדת הדין to those people whose soul was rooted in the שרש, the hidden domain since they possessed the חיה and יחידה dimension of soul. This approach also explains the answer G–d is reported to have given to Moses to whom He had shown a vision of the life and death of Rabbi Akiva, and who questioned how G–d could allow such a man to be tortured to death (Menachot 29). The words G–d reportedly used were שתוק, כך עלה במחשבה לפני , "Be silent so it suits My plan." Normally, we understand this answer as a warning not to question G–d's ways when these seem beyond our understanding. However, this is not what G–d meant to convey by this answer. G–d simply explained that people such as Rabbi Akiva who are part of the בני עליה can be judged by higher standards than ordinary people, and therefore G–d applied the מדת הדין when judging them.

Let us return to the subject of Nadav and Avihu. These two sons of Aaron did not restrain themselves and, as a consequence beheld a vision that was beyond the capacity of their bodies; this was what caused their death. Theirs was the death described as precious to the Lord in Psalms 116,15. Their "death" should not be considered a regular death, and we must not think of it in terms of their being punished for a sin and having to die. On the contrary, they had achieved such a close affinity with G–d that their souls simply remained in the Celestial Regions, i.e. בקרבתם לפני ה'. This is the reason Moses told Aaron that theirs was an example of בקרובי אקדש, "I will be sanctified through those who are close to Me" (10,3). What this means is that their very death was the beginning of their life in the Hereafter. They may therefore be perceived as having entered the פרדס and having emerged unscathed. Since their departure from earth occurred when they were publicly preparing to enter into the most intimate relationship with G–d, it was of the "על פני כל העם אכבד" type, viz. 10,3. Rabbi Akiva suffered a similar fate when he died on קדוש השם, a martyr at the hands of the Romans. He sanctified G–d's name after having emerged from the פרדס, albeit sometime later. When the angels demurred about the fate of Rabbi Akiva and the other nine Martyrs, [cf. the liturgical prayer אלה אזכרה in the Mussaph service of the Day of Atonement. Ed.] G–d silenced them by saying that this was His decision. Here too we find that Aaron remained silent after Moses had explained the nature of his sons' "deaths" to him. This then is the explanation of the first Mishnah in Avot.