Conversion as we understand it (a period of formal learning, circumcision for males and immersion in a mikveh after having been assessed by a rabbinic court) is a rabbinic, rather than Biblical, invention.
We must acknowledge a discussion of Jewish identity and status is likely to be anachronistic.
Even ‘Judaism’ is problematic in a Biblical context because in the world views of ancient cultures, one’s God was tied to tribe and territory.
Biblical narratives of non-Israelites becoming Israelites challenge that. Abraham and Sarah are the first converts. Their designation as ‘Ivrim’ is not incidental: they were the first boundary-crossers; not just of the Euphrates river, but spiritually as well. The Torah tells us they ‘made souls in Charan’ (Gen. 12:5).
In the Exodus from Egypt, we learn an ‘erev rav’, a mixed multitude of Egyptians, joined the Israelites in significant numbers – one in five! (Ex. 12:38). No fewer than 36 times does the Torah caution us to love the ‘ger’, the stranger – a word meaning immigrant and convert.
The post-exilic Prophetic literature makes a quantum leap into a universalist narrative. Amos and Isaiah affirm the openness of the covenant with the God of Israel. Ruth the Moabite, from a despised community, pledges ‘your people will be my people, your God my God’ (Ruth 1:16) and Jonah is sent on a mission to extend God’s mercy to the nations of the world by example of Nineveh, arch-enemy of the Jews.
Maybe the Bible doesn’t give us rules on what conversion is supposed to look like, but it does give us an ethos of welcoming. Questions of conversion dance between the universalist and the particular.
What the Bible is clear on is that we are to love, cherish and celebrate those who strengthen our ranks.
υ Rabbi Esther Hugenholtz, Sinai Synagogue, Leeds