Komentaryong Sumisipi para sa Isaias 1:3

Righteous, they are called “My people.” You might ask: Do we not find “my people” referring to them when they are wicked, as it says “my people do not consider” (Yeshayah 1:3). The answer is that the verse means that beforehand they were my people, but now “they do not consider.”

ארבעים יכנו ולא יוסיף, “he shall strike him forty and he shall not add.” This amount of lashes is a judgment by itself, a heavenly decree [not the result of an assessment by the judges of the severity of the sin. Ed.] The judge is bound to sentence the guilty party to this sentence only, and the convicted party must endure it. One must not increase the number of lashes so as not to humiliate the convicted party.
Our sages in Makkot 22 elaborate on the precise manner in which this beating is administered. The two hands of the victim are bound in two opposing directions to a kind of wooden board. The person administering the lashes takes hold of the guilty party’s clothing, exposing his chest. A stone is placed underneath him from behind. The person deputized to perform the beating (known as חזן הכנסת) stands over the prisoner with the belt made of calf-leather in his hand (and proceeds). This belt is folded over and folded over again so that it is actually four strips of belt. In addition there are belts of donkey hide interspersed to connect the other four strips with the ones made of calf-hide. The handle of the belt is one handbreadth wide and one handbreadth long. The beatings are administered one third to his chest and the other two thirds to his back. The reason the portion of not muzzling an ox while it is in the act of threshing is written immediately after this verse is to teach that the belt should be made of calf-hide.
The reason why the measurements of one handbreadth width and length respectively, and the total number of leather strips in that belt (whip) are important, is connected to the fact that a handbreadth is four fingers wide. When we fold this over we get eight finger widths and when we do this a third time we have 16 fingerbreadths. There is not a single commandment in the Torah the violation of which does not involve a minimum of violating 16 covenants. Hence the number 16 has a deep symbolic significance in the administering of the penalty for violating a negative commandment. (compare Sotah 37) The reason that two (kinds of) belts which interconnect upwards and downwards between the calf hide belts are used is to allude to the violation by the sinner of both his undertaking implied in the word נעשה and the word נשמע “we will do and we will hear (learn),” which was the formula by which the people of Israel had accepted the Torah. The reason both calf-hide and donkey-hide is used is to combine “ox and donkey.” This is an allusion to the lament of the prophet Isaiah that whereas both an ox and a donkey are smart enough to know and respect their owners, only the sinful Jewish people appear not to possess such minimal intelligence (Isaiah 1,3). Anyone who transgresses the commandments of His Maker deserves to be disciplined by lashes from a belt consisting of both calf-hide and donkey-hide.

I have found in Pirke d'Rabbi Eliezer chapter 45 that Aaron found amongst the golden jewelry contributed by the people a headband on which the tetragrammaton had been inscribed. It also had engraved on it the likeness of a calf. According to Rabbi Eliezer this was the only piece of gold Aaron threw into the crucible. He based himself on the fact that the Torah did not quote Aaron as saying ואשליכם באש, “and I threw them (the contributions of golden jewelry) into the fire, but he said: ואשליכהו באש, I threw it into the fire (verse 24). When the Israelites witnessed a golden calf emerging, this was perceived as a miracle especially since the calf was heard to low, to moo, and this is why they mistakenly ascribed prophetic or divine powers to this golden calf.
Rabbi Yehudah said that Samael entered the calf and lowed, making the Israelites think that the calf itself was capable of mooing and therefore was alive. He bases himself on the verse in Isaiah 1,3 that “every ox knows its owner,” i.e. that every creature acknowledges its Creator by its mouth. Thus far Pirke d'Rabbi Eliezer.