Q. Why does the Siddur refer to gerei hatzedek, righteous converts? Are there any other kind?
A. In ancient times there were two categories of gerim, the ger tzedek – the “righteous” or full convert – and the ger toshav – the “resident alien” or partial convert. The full convert chose to join the people of Israel and accept the Israelite God. The partial convert, living amongst Israelites, followed Jewish practices such as Pesach (Ex. 12:48), Yom Kippur (Lev. 16:29) and ritual purity (Num. 19:10).
The full convert joined the Jewish people out of belief and conviction. Isaiah (56:6) describes such a person as “one who joins himself to God”. The term ger tzedek, “righteous convert”, indicates that full conversion is without ulterior motives. Rabbinic literature is full of praise of such converts. The Midrash says: “Dearer to God is the proselyte who has come of his own accord than all the crowds of Israelites who stood before Mount Sinai… for the proselyte took the yoke of Heaven upon himself” (Tanchuma, Lech L’cha). However, there are also negative views, presumably reflecting the fact that some converts defected from Judaism.