Researcg Query: Source of Piyyut (?) Fragment

Jacob Adler's picture

Dear Colleagues,

In the philosophical part of Simeon ben Tsemah Duran's Magen Avot, Duran quotes the following line:
איך סוד יסוד הכל עין רעיון כסה תבין ולא בנת יסודך
He doesn't say where it's from beyond indicating "amar ha-payyat be-sifro," so I assume it's from some piyyut.  Can anyone identify the source?
Jacob Adler
University of Arkansas
Philosophy Department
Fayetteville, Arkansas, USA