Does Exodus 12:43-49 mean that a stranger in the land must become a covenant member before he or she can be treated equally under the law?
No. Consider the following verse:
21 'Ye do not eat of any carcase; to the sojourner who is within thy gates thou dost give it, and he hath eaten it; or sell it to a stranger; for a holy people thou art to Jehovah thy God; Deuteronomy 14:21YLT
There are actually two different words for foreigner (ger and nekhar) in this verse, even though some translators render them with the same noun in the target language. The difference between ger and nekhar in the above verse is functional. It seems to imply that the nekhar is something like a foreign trader who is wealthy enough to purchase food, and the ger is a foreign sojourner who is poor and begging at the gates.
Covenant members were forbidden from eating "anything that dies of itself". But sojourners(ger) were allowed to. If sojourners/ger were equivalent to covenant members, they would also have been forbidden from eating it, because it was considered (ceremonially) "unclean". This shows that ger were not always converts.
Therefore, it seems to me that sojourners(ger) were only required to be circumcised covenant members if they wanted to participate in the Passover. Even if sojourners(ger) weren't circumcised, they were still protected by Biblical law.
Biblical law contains many explicit distinctions between persons to whom the law applies differently at different times/situations (such as the example I gave above). There are distinctions between men and women, servants and masters, sojourners and native, etc.
Exodus 12:49 says:
49 one law is to a native, and to a sojourner who is sojourning in your midst.' Exodus 12:49YLT
I don't think we can take this as meaning "Biblical law applies -- in every respect -- the same to the ger as to the native covenant member. That would directly contradict the verse that I cited above (and God does not contradict himself).
I think verse 49 is just summarizing the following general principle:
- Biblical law applies -- as a whole, and respecting its own distinctions -- to everyone in the land.
No one is considered to be an "outlaw" (not protected by the law) merely because they are foreign-born.
