Rabbi Aharon Roth, "Reb Arele", was born in 1894 in Ungvár (Uzhhorod), Hungary, the son of Shmuel Yaakov, a butcher in the town. He studied in the yeshiva of Rabbi Yeshaya Silberstein of Vác and in that of Rabbi Moshe Farhand, as well as in Munkács. He attached himself to many tzaddikim of his generation, including Rabbi Yehosef Rottenberg of Kossoni and Rabbi Yehoshua Heschel Fried of Kapisch, but above all to Rabbi Yissachar Dov of Belz, with whom he stayed nine months on his first visit.

He founded the Shomer Emunim Chassidic movement. In the 1920s he drew a circle of fervent followers in Satu Mare (Satmar) and in the 1930s in Beregszász. He then moved to Jerusalem, where he established his community. His teaching stresses simple faith, ardent prayer, joy and purity. His works, Shomer Emunim, written in 1942 in reaction to news of the Nazi atrocities, Shulchan HaTahor and Taharat HaKodesh, have become classics of contemporary Chassidic literature.

He passed away on 6 Nisan 5707 (1947) and rests on the Mount of Olives. After his death his followers divided between Shomrei Emunim, led by his son Rabbi Avraham Chaim, and Toldot Aharon, led by his son-in-law, from which Toldot Avraham Yitzchak later branched off; they remain very present in Jerusalem and Bnei Brak.