"BTW it's in magein avot mode, not freygish. Freygish has a flat second and a major third. "

Slave's Lament uses the harmonic minor scale, which differs from the Western minor scale in that the 7th note is raised a half step.

The Freygish mode (same as the Ahavah Rabbah) and the harmonic minor scale have the same sequence of intervals (half-tones, whole-tones, and augmented-whole-tone), the only difference is where you designate the tonic. They both have that distinctive augmented-whole-tone interval (one-and-a-half-tone interval).

The Magein Avot mode (same as the Western minor) has only whole- and half-tone intervals.
See Jewish prayer modes

S. in Seattle