גר, ger, means an alien. תושב, toshav, means a resident. What does it mean to be an alien and a resident?
These two words are seen together in two forms: 1) with a vav in the middle ger v'toshav and 2) without a vav, ger toshav. These combinations are seen infrequently, but three time in Leviticus 25.
(מז) וְכִ֣י תַשִּׂ֗יג יַ֣ד גֵּ֤ר וְתוֹשָׁב֙ עִמָּ֔ךְ וּמָ֥ךְ אָחִ֖יךָ עִמּ֑וֹ וְנִמְכַּ֗ר לְגֵ֤ר תּוֹשָׁב֙ עִמָּ֔ךְ א֥וֹ לְעֵ֖קֶר מִשְׁפַּ֥חַת גֵּֽר׃
(47) And if a stranger who is a settler with thee be waxen rich, and thy brother be waxen poor beside him, and sell himself unto the stranger who is a settler with thee, or to the offshoot of a stranger’s family,
The two forms are parallel text -- meaning that they both are indicating a person who is a resident and a stranger.
(לה) וְכִֽי־יָמ֣וּךְ אָחִ֔יךָ וּמָ֥טָה יָד֖וֹ עִמָּ֑ךְ וְהֶֽחֱזַ֣קְתָּ בּ֔וֹ גֵּ֧ר וְתוֹשָׁ֛ב וָחַ֖י עִמָּֽךְ׃
(35) And if thy brother be waxen poor, and his means fail with thee; then thou shalt uphold him: as a stranger and a settler shall he live with thee.
Shem Olam, a work written by the Chofetz Chaim, explains that ger and toshav are two different people in this case. He explains that sometimes the vav can be "and" and sometimes it can be "or." For this verse, he says "or" because a ger would refer to an actual convert and a toshav would be a stranger who happens to live with you/near you.
(כג) וְהָאָ֗רֶץ לֹ֤א תִמָּכֵר֙ לִצְמִתֻ֔ת כִּי־לִ֖י הָאָ֑רֶץ כִּֽי־גֵרִ֧ים וְתוֹשָׁבִ֛ים אַתֶּ֖ם עִמָּדִֽי׃
(23) And the land shall not be sold in perpetuity; for the land is Mine; for ye are strangers and settlers with Me.
In this case, the people being discussed are all of the Israelites as the land is actually God's, so they are a resident on the property, but it is not really theirs.
(ד) גֵּר־וְתוֹשָׁ֥ב אָנֹכִ֖י עִמָּכֶ֑ם תְּנ֨וּ לִ֤י אֲחֻזַּת־קֶ֙בֶר֙ עִמָּכֶ֔ם וְאֶקְבְּרָ֥ה מֵתִ֖י מִלְּפָנָֽי׃
(4) 'I am a stranger and a sojourner with you: give me a possession of a burying-place with you, that I may bury my dead out of my sight.'
After learning about the different meanings of these two words, there are two interpretations:
- Shem Olam states that in this case, the focus is that Abraham is a stranger who wishes to eventually become a resident.
- Rashi explains that the difference between the two terms is who is describing him. The people of that land, the B'nei Chet, see Abraham as a stranger, whereas, God, sees Abraham as a resident since the land has been given by God to him. Abraham states these two terms because he is telling the people that he hopes they deal kindly with him as he is a stranger, but also warns them that if they don't, he will take the land that is his according to God.