The Severity of the Prohibition of Idolatry
חומרת איסור עבודה זרה
It is a mitzva to believe in God, that He is the sole Creator of the world and its Guide, and it is forbidden to believe that there is any other deity besides Him, as it is stated (Shemot 20:2-3): "I the Lord am your God who brought you out of the land of Egypt, the house of bondage. You shall have no other gods besides Me." This prohibition is called avoda zara (idolatry, literally "foreign worship"). Its meaning is that instead of believing that God is the Creator and Sustainer of the world, the Master of all forces, and that only He is fit to be worshiped, one believes that foreign forces besides Him possess independent power, and he worships them in order to derive benefit from them.
Idolatry in shituf (association) is also forbidden. That is, even one who knows that God is the God of gods, if he believes that alongside Him or beneath Him there is an additional power that has the choice to decide how to act, and therefore he worships it too in order to receive its help, he is practicing idolatry in shituf, and his law is like that of one who worships idols, as it is stated (Shemot 20:3): "You shall have no other gods besides Me" (Rambam, Yesodei Ha-Torah 1:6; Yere’im 243; Semag, negative commandment 1; below, halakha 4).
The Sages said (Sifrei, Re’eh 54): "Whoever acknowledges idolatry denies the entire Torah, and whoever denies idolatry acknowledges the entire Torah." We likewise learn this from what is stated (Bamidbar 15:22-23): "If you unwittingly fail to observe any of these commandments that the Lord has spoken to Moshe – anything that the Lord has commanded you through Moshe, from the day that the Lord commanded and onward throughout your generations." The Sages explained that this refers to the mitzva that is equivalent to all the mitzvot, namely idolatry, and it is the mitzva "that the Lord has commanded you," for the first two commandments of the Ten Commandments, "'I am' and 'You shall have no' – we heard them from the mouth of the Almighty" (Horayot 8a; Rambam, Avoda Zara 2:4).
The Sages said (Kiddushin 39b) that the prohibition of idolatry is more severe than all other sins. For with all other sins, a person who thought an evil thought but did not come to act upon it is not punished for his thought, whereas with idolatry one is punished even for an evil thought, as it is stated (Yeḥezkel 14:5): "That I may seize the House of Israel by their hearts, because they have all been estranged from Me through their idols."
Because of the great severity of the prohibition of idolatry, a Jew is commanded to give up his life rather than desecrate God’s Name through idolatry, as it is stated (Devarim 6:4-5): "Hear, O Israel, the Lord is our God, the Lord is One. And you shall love the Lord your God with all your heart and with all your soul and with all your might." "'With all your soul' – even if He takes your soul" (Mishna Berakhot 9:5). It is likewise stated (Vayikra 22:32): "You shall not profane My holy Name, that I may be sanctified in the midst of the Children of Israel; I am the Lord who sanctifies you." The laws of mesirut nefesh (self-sacrifice) will be explained at length below in chapter 4.
One who deliberately worships idols before witnesses, after they warned him and cautioned him not to worship idols, is liable to death by stoning, as it is stated (Devarim 17:2-7): "If there is found among you, in one of your settlements that the Lord your God is giving you, a man or woman who does what is evil in the eyes of the Lord your God, transgressing His covenant, and has gone and worshiped other gods and bowed down to them, or to the sun or the moon or any of the host of heaven, which I did not command; and it is told to you and you hear of it, then you shall inquire thoroughly, and behold, it is true, the thing is certain, this abomination has been done in Israel – you shall take out that man or that woman who has done this evil thing to your gates, the man or the woman, and you shall stone them with stones, and they shall die. By the testimony of two witnesses or three witnesses shall the one who is to die be put to death; he shall not be put to death by the testimony of one witness. The hand of the witnesses shall be first upon him to put him to death, and the hand of all the people afterward; so shall you eradicate the evil from your midst."