The Sifra - Halakic midrash to Leviticus. It is frequently quoted in the Gemara, and the study of it followed that of the Mishnah, as appears from Tanḥuma, quoted in "Or Zarua'," Like Vayikra itself, the midrash is occasionally called "Torat Kohanim"
This is the bridge from the Text of the Torah to the Halacha. Below is the Halachik Medrash on our Pasuk.
() [א] בא ואמר "גר אני" יכול יקבלו? תלמוד לומר "אתך"-- במוחזק לך. את שבאו עדים מנין? תלמוד לומר "בארצכם". אין לי אלא בארץ, בחוץ לארץ מנין? תלמוד לומר "אתכם"-- בכל מקום שאתם. אם כן למה נאמר "בארצכם"? אלא בארץ צריך להביא ראיה ובחוץ לארץ אין צריך להביא ראיה.
(undefined) 1) (19:33) ("And if there dwell among you a stranger (i.e., a proselyte) in your land, you shall not oppress him.") If one came and said; I am a proselyte, I might think that he is to be accepted (as such); it is, therefore, written "among you" — when he is acknowledged among you (to be a proselyte). If he comes along with his witnesses (that he is a proselyte), whence is it derived (that he is to be accepted)? From "And if there dwell, etc." "in your land": This tells me (that they are accepted) only in Eretz Yisrael. Whence do I derive (the same) for outside the land? From "among you" — wherever you are. If so, why is it written "in your land"? In your land he must bring proof (that he is a proselyte); outside the land he need not bring proof.
() [ב] "לא תונו אותו"-- שלא תאמר לו "אמש היית עובד עבודת כוכבים והיום נכנסת תחת כנפי השכינה".
(undefined) 2) "you shall not oppress him": You shall not say to him: "Yesterday you were an idolator, and today you have entered under the wings of the Shechinah!"
() [ג] "כאזרח"-- מה אזרח שקבל עליו את כל דברי התורה אף גר שקבל עליו כל דברי התורה. מיכן אמרו גר שקבל עליו את כל דברי התורה חוץ מדבר אחד-- אין מקבלים אותו. ר' יוסי בר' יהודה אומר, אפילו דבר קטן מדקדוקי סופרים.
(undefined) 3) (19:34) ("As the home-born among you shall he be to you, the stranger that lives among you." And you shall love him as yourself, for you were strangers in the land of Egypt; I am the L rd your G d.") "As the home-born": Just as the home-born takes upon himself all the words of the Torah, so, must the proselyte take upon himself all the words of the Torah. From here they ruled: If a proselyte took upon himself all the words of the Torah except one, he is not to be accepted. R. Yossi b. R. Yehudah says: Even (if he did not accept) a small thing of the inferences of the Scribes.
() [ד] "יהיה לכם הגר הגר אתכם ואהבת לו כמוך"-- כשם שנאמר לישראל "ואהבת לרעך כמוך" כך נאמר לגרים "ואהבת לו כמוך". "כי גרים הייתם בארץ מצרים"-- דעו מנפשם של גרים שאף אתם הייתם גרים בארץ מצרים.
(undefined) 4) "shall be to you the stranger that lives among you. And you shall love him as yourself." Just as it is written of Jews (Ibid. 19:18) "and you shall love your fellow as yourself," so is it written of proselytes "and you shall love him as yourself." "for you were strangers in the land of Egypt": Know the soul of the strangers, for you yourselves were strangers in the land of Egypt."