Yerushalmi Megillah 4:9 ירושלמי מגילה ד׳:ט׳

MISHNAH: If somebody said, I shall not stand before the Ark in coloreds, also in whites he shall not stand. With sandals I shall not stand, also barefoot he shall not stand¹⁴⁹We suspect him of belonging to a heretical sect which does not follow pharisaic/rabbinic instructions, such as the Jewish sect in Arabia from whom Mohammed received the ways of divine worship, who did not follow the rabbinic reduction of 5 daily prayers (2 times Shema` and 3 times Amidah) to 3.. He who makes his tefillah round puts himself in danger and it is no meritorious deed¹⁵⁰When Jewish worship was forbidden during the Hadrianic persecutions, changing the traditional forms of tefillin is not acceptable.. If he places it on his forehead or on his hand, it is the way of heretics¹⁵¹Since the verse (Ex. 13:9) requires a sign on your hand and remembrance(or declaration) between your eyes, Sadducee Tefillin were put on the hand and on the forehead between the eyes, in contrast to rabbinic practice which puts them above the elbow and on the hair.. If he covered it with gold and put it on his sleeve, it is the way of outsiders¹⁵²Non-Jewish gnostic sects..

HALAKHAH: Rebbi Yose ben Bevai stated: Square [black]¹⁵³Corrector’s addition, of unknown source. The Babli only declares black strips as practice from Moses on Sinai. tefillin are practice from Moses on Sinai¹⁵⁴Babli 24b, Šabbat 28b, Menaḥot 35a..