Halakhah for Sanhedrin 107:15

To not curse the judge: To not curse the judges, as it is stated (Exodus 22:27), "Lords (elohim) shall you not curse." And the understanding of elohim [here] is judges, as [in] (Exodus 22:8), "that the elohim deem guilty." And the verse [chose] this expression [which can also mean, God], so that another negative commandment would be included in this negative commandment, and that is the negative commandment of 'blessing' God. As they, may there memory be blessed, said in the Mekhilta and the Sifri, "The warning for 'blessing God' is from that it is written, 'Elohim shall you not curse.'" And that which is written in another place, "And the one that blasphemes the name of the Lord will surely die" (Leviticus 24:16), is [the mention of] its punishment. But the warning (prohibition) is from here. As mention of the punishment of a commandment without its warning is not sufficient for us. And this is what our Rabbis, may their memory be blessed, always said (Sanhedrin 54a), "We have heard the punishment, from where is the warning?" And the matter is because of this: That if the prevention of God did not come to us in the matter, but it would [only] state, "One who does thing x will be punished with this," it would be implied that there is permission to transgress the commandment in the hand of anyone who is willing to take the punishment and is not concerned with his pain, and that he will not go against the will of God and His commandment with this. And [so] the matter of the commandment will turn into a type of give and take, meaning to say that one who wants to do thing x, can give such and such and do it, or bare his shoulder to suffer such and do it. And the intention of the commandments is not like this, but rather that God prevented us from things for our [own] good, and informed us in some of them of the punishment that comes to us immediately, besides transgressing His will, which is weightier than anything. And this is [the meaning] of that which they, may their memory be blessed, said in every place (Yoma 81a), "He did not punish, unless He warned," meaning to say, God did not inform of the punishment that comes for a sin, unless He first informed us that His will is that we do not do that thing for which the punishment is coming.