The famous haunting melody of Ani Maamin is attributed to Reb Azriel David Fastag, a Modzitzer chossid whose compositions were regularly sung in the court of the Modzitzer Rebbe, Rav Shaul Yedidya Elazar.
Reb Azriel Dovid reportedly composed the tune in a cattle car while being taken to Treblinka. He announced that he would give half of his share of the World to Come to whoever would bring the tune to the Modzitzer Rebbe, who had escaped Europe in 1940.
Two men took him up on his offer and leaped from the moving train. One died from the fall, but the other survived and eventually brought the tune to the Rebbe’s son in Eretz Yisroel, who sent his father the musical score. The tune was sung by hundreds of Jews as they marched to the gas chambers in the Nazi death camps.
In the following video, Rabbi Bentzion Shenker, the legendary composer of musical secretary for the Modzitzer Rebbes for decades, shares the story of “the Fastag Ani Maamin.”