He urges his coreligionists to send young men to Constantinople to study their religious authorities, lest their faith die out, and to lead a pious life; otherwise he would pronounce an anathema on those derelict in their duties.
He devoted himself to the improvement of the intellectual condition of the Karaite etc., which, in consequence of internal dissensions on religious matters, was at that time very low.
In order to settle the religious laws he compiled a code entitled Aderet Eliyahu (The Mantle of Elijah).
This code, which contained both the mandatory and prohibitory precepts, is rightly regarded by the Karaites as the greatest authority on those matters.
In it Bashyazi displays a remarkable knowledge, not only of the earliest Karaite writings, but also of all the more important rabbinical works, including those of Saadia Gaon, Abraham ibn Ezra, and Maimonides, whose opinions he discusses.
This last subject comprises three parts: theology; ethics; and laws concerning prayers, synagogues, slaughtering, clean and unclean, prohibited degrees in marriage, niddah, the years of release and jubilee, the prohibition of Shatnez, and oaths.
Bashyazi's theological system is a masterpiece of clarity and logical precision[citation needed].
Following the example of Judah Hadassi and probably of still older masters of Karaism, he set up ten articles of belief, the veracity of which he demonstrates philosophically as follows: (1) All physical existence—that is to say, the celestial spheres and all that they contain—has been created.
However, not satisfied with religious proofs only, Bashyazi tries to give philosophical arguments, and being unable to furnish them in the strictly Peripatetic way, he demonstrates his article of belief by Avicenna's theory of "the necessary" and "the possible," which he wrongly attributes to Aristotle.
Bashyazi examines prophecy from the philosophical point of view; and, demonstrating it to be true, he claims that there is no hindrance to a belief in Moses' mission.
This article of belief being in close connection with Providence and Omniscience, Bashyazi refutes the opinion of certain philosophers who assert that God's knowledge bears only upon the universalities and not upon individual things.
(10) That God did not reject the exiled [Jews], and that although they are suffering, they should hope every day for their deliverance by the Messiah, the son of David.
The other works of Bashyazi are: (1) Iggeret ha-Tzom (Letter on Fasting on Saturday), divided into three sections.
This letter was directed against Solomon Sharbit ha-Zahab, who opposed the opinion of Aaron ben Elijah the Karaite.
(6) Melitzat ha-Mitzvot (The Precepts in Verses), imitated from the Azharot of Solomon ibn Gabirol.