The Torah considers one who strays from the path of Hashem to be an idol-worshipper. He who serves idols is tantamount to one who repudiates the entire Torah. Idolatry is a rejection of the Almighty. One who does not firmly believe and accept Hashem as the Supreme Ruler and Creator of the world apparently spurns His mitzvos and Torah.
In Megillas Esther 2:5, the pasuk refers to Mordechai as “Ish Yehudi.” The Talmud in Megillah 12b explains the term “Yehudi” as an appellation describing one who is “kofer b’avodah zarah,” denies idol worship. Mordechai was called a Yehudi, not because he descended from the tribe of Yehudah, which he did not, but rather because of his firm denial of avodah zarah. Bisyah bas Pharaoh saved Moshe Rabbeinu and took him into Pharaoh’s palace to be raised and protected as a child. In Divrei Hayamim I, 4:18 she is referred to as “Yehudiah,” because she repudiated her father’s idols and converted to Judaism.
The word “yehudi” originates from hodah/modeh, which means admit/concede. Leah named her fourth son Yehudah, saying, “Now I will thank Hashem.” To demonstrate gratitude is to concede that one has benefited from someone else. A Yehudi is one who manifests his gratitude to the Almighty and who proudly, throughout his entire demeanor, recognizes Hashem Yisborach as the source of everything that exists. He shows his allegiance to Hashem in his commitment to serve Him through the observance of His mitzvos.
We may add that idol-worship has many faces and names. One does not have to genuflect to a stone god in order to be considered an idol worshipper. If one demonstrates loyalty to anything, such as a movement based upon theological deliberation, an endeavor or line of thinking that is antithetical to Torah — or just simply relegates Hashem, His Torah and mitzvos to second place, he is guilty of worshipping an entity other than Hashem. The most common form of idol worship is self-worship. We are the greatest idols! We take care of ourselves – first, then we respond to the needs and demands of others even those of Hashem. One cannot view himself as a true Yehudi as long as he is obsessed with vain, glorious self-gratification. A Yehudi is one who unconditionally sublimates himself to Hashem. Otherwise, his self-defined brand of Yahadus is nothing more than an exercise in arrogance.
