2,154. Converts from the Seven Canaanite Nations

Hilchos Issurei Biah 12:22

A member of the seven Canaanite nations who converts is not prohibited by Biblical law from marrying into the general Jewish marriage pool, though only the Gibeonites actually did so. Since they acted through subterfuge, Yehoshua ruled that the both their men and their women should be prohibited to marry into the general Jewish marriage pool. This prohibition only applies when the Temple is standing since Joshua 9:23 specifies that they would be wood-choppers and water-drawers for the Temple. Their ban is therefore dependent on the Temple.

Hilchos Issurei Biah 12:23

The Gibeonites are called Nesinim (“given”) because they were given over for the service in the Temple. David later ruled that they should never be allowed to join the general Jewish marriage pool, even when the Temple isn’t standing. This is explicit in Ezra 8:20, “From the Nesinim, whom David and the princes gave over for the service of the Levites.” We see that he made the matter independent of the Temple.