The Sojourner among you…becoming an Israelite meant following the rules
When the law given to Moses came into being, Israel clearly became a nation set apart for a special purpose:
“…and you shall be unto Me, a kingdom of priests, and a holy nation” (Exo 19:6). In plain English: what set the Hebrews apart from others is not that they were smarter, prettier or more moral (as they certainly were not). However, a few factors made them stand out from the crowd. They knew what had transpired in Eden, i.e. they acknowledged mans’ fallen nature. Until one acknowledges their sin they can never know the Lord. (Two), they understood what idolatry was in its many forms and (three) and they acknowledged and worshiped the God of Heaven and earth (YHVH, I AM, or in the English language, Jehovah). Other nations languished in ignorance or willfully worshiped idols they themselves had created. Others devised all sorts of philosophies to control and explain away nature. At the other end of the spectrum, people feared “the spirits of nature” along with its celestial bodies, and still others created any number of labels and religions, none of which pertained to our Creator.
So Israel had a big job to do. Be true to the real Lord, then teach others, so that foreigners having true conversion would acknowledge their Father and in turn they would be blessed. Strict rules had to be followed by natural-born Hebrews, as well as those conquered peoples from whom the Israelites took land and for foreigners choosing to live among the Israelites known as Sojourners.
Sojourners differed from visitors in that these settled permanently with the Israelites and they weren't servants. Throughout, Israelite law reflected the need to accommodate these newcomers. Exodus 12:43-49, makes a distinction regarding those just passing through versus those living among the Hebrews. Any foreigner expressing a desire to become an Israelite would then be required to follow their commandments by worshiping the true God, having their males circumcised and observing all the festivals (Passover is specifically mentioned in this passage). “One law shall be to him that is home-born, and to the stranger that sojourns among you” (v.49).
The Lord had tender regard for sojourners who were not of Jacob’s line as witnessed in a passage from Isaiah 56:3-8:
"Neither let the child of the foreigner, who has joined himself to the LORD, speak, (in despair that is) saying: ‘The LORD has utterly separated me from His people’…(v.6)…Also the sons of the stranger, that join themselves to the LORD, to serve Him, and to love the name of the LORD, to be His servants, every one that keeps the sabbath from polluting it, and takes hold of my covenant; (v.7) Even them will I bring to my holy mountain, and make them joyful in my house of prayer: their burnt offerings and their sacrifices shall be accepted upon mine altar; for mine house shall be called an house of prayer for all people. (v.8) The Lord GOD who gathers the outcasts of Israel says: Yet will I gather others to Him, beside those that are (already) gathered unto Him."
Notice Isaiah mentioned the words Sabbath and Covenant in v.6 from that chapter. All are welcomed in God’s congregation provided they acknowledge His will and way. Israelites true to YHVH would never have allowed people of other faiths into their congregation, nor into the Lord’s sanctuary. When Israel strayed by allowing apostasy and idolatry, they suffered spiritually and physically by loss of land, people and divine help.
In this next section, a vision is described where God’s Temple becomes a polluted sanctuary for all the idolatrous influence. This little vision is a glimpse into what now is becoming the norm and what will soon become mandatory.