הֵ֣ן גּ֥וֹר יָג֛וּר אֶ֖פֶס מֵֽאוֹתִ֑י מִי־גָ֥ר אִתָּ֖ךְ עָלַ֥יִךְ יִפּֽוֹל׃
Si alguno conspirare contra ti, será sin mí: el que contra ti conspirare, delante de ti caerá.
Yevamot
The rabbis taught: Converts are not accepted in the messianic era; ... similarly, they did not accept them in the times of David and Solomon.