He was famous for his vast Torah knowledge and many rabbis from Italy and France would send him questions which he would answer clearly and concisely.
He became famous for his important kabbalistic work Shomer Emunim, in which he clarifies the truths of Kabbalah.
Through this work he debates with Rabbi Emanuel Chai Ricci who supported the literal interpretation of Tzimtzum.
[5] His work is considered a foundational text in Kabbalah and the most prominent representative of the non-literal view of Tzimtzum.
Ergas responded with two polemical books called Tokhakhat Meguleh and HaTzad Nachash which he printed in London in 1715.