“When Achior saw all that the God of Israel had done, he believed firmly in God. So he was circumcised, and joined the house of Israel, remaining so to this day.” – Judith 14.10 (NRSV) 
In the Judith 14.10, Achior becomes a proselyte within the house of Israel. It is interesting to note that at least to the author of the Book of Judith that they seemed to have no problem in letting Achior within the house of Israel. Since it should be noted that Achior isn’t just any sort of pagan, he’s an Ammonite, a chief leaders, as evidence by Judith 5.5a “Then Achior, the leader of all the Ammonites.”
But if one remembers Deuteronomy 23.3 it reads that “No Ammonite or Moabite shall be admitted to the assembly of the Lord. Even to the tenth generation, none of their descendants shall be admitted to the assembly of the Lord,”” So before even going any further, when one looks at Achior, we see in him one of the most unlikeliest men to convert to Judaism.
Despite the rule in Deuteronomy, the Book of Judith has Achior converted. There are of course a variety of different reasons given to why Achior might have been exempted from the rule. Perhaps he was a special case (as was Ruth the Moabitess), perhaps the prohibition has past, Achior being past the tenth generation, or maybe the author is even just expressing the same “universalism,” of the book of Jonah.
In any case, despite who Achior is racially, the author of Judith clearly wishes for him to be seen in the light of the other righteous Gentiles of the bible. Achior is said to believe “firmly,” or “exceedingly, the greek word being σφόδρα which Crowley say “must mean ‘with all his heart,’” Thus Achior is indeed a genuine conversion, moreover he moves from the simple “God fearer,” sort of Gentile and now into full proselytism, and hence has “bound himself,” the laws which accompany that.
So that in spite of all the difficulties which Achior brings, he becomes a symbolic invitation to other would be converts, to the author, Achior is not one secluded case, but instead a representative of all gentiles who would wish to come to faith in the God of Israel.
 In this post, Judith will be assumed to have been written during the Maccabean age and thus the author of the Book of Judith will be seen as giving testimony to at least one line of Jewish thought during that period. Also, this brief note will likely be accompanied by an article further dealing with the people of God as seen in the Old and New Testaments.
 Benedikt Otzen, Tobit and Judith (London; New York: Sheffield Academic Press, 2002), 107.
 Carey A. Moore, Judith: A New Translation With Introduction and Commentary, Includes Indexes. (New Haven; London: Yale University Press, 2008), 235
 Otzen, 108.
A.E. Cowley, “Judith,” in The Apocrypha and Pseudepigrapha of the Old Testament in English, ed. Robert Henry Charles (Oxford: Clarendon Press, 1913), 1:264.
 John Peter Lange, Philip Schaff and Edwin Cone Bissell, A Commentary on the Holy Scriptures: Apocrypha (New York: Charles Scribner’s Sons, 1890), 194.
 Craghan, 112-3