Sefer Nestor Ha-Komer or The Book of Nestor the Priest (c.900 CE) is the earliest surviving anti-Christian Jewish polemic. The book is in Hebrew, but also exists in an Arabic translation. It cites extensively and critically from New Testament and Church sources. The title komer (כומר) describes a Christian priest (in modern Hebrew the word is used both for Catholic or Orthodox priests and for Protestant ministers), rather than a kohen or Jewish priest.
The text uses the spelling Yeshu (ישו) for Jesus.
A modern edition פולמוס נסתור הכומר The Polemic of Nestor the Priest by Daniel J. Lasker and Sarah Stroumsa was published by the Ben-Zvi Institute for the Study of Jewish Communities in the East, 1996.
References
Nestor the priest Wikipedia(Text) CC BY-SA