Midrash su Isaia 14:1

(Fol. 47) Our Rabbis were taught: When a proselyte comes and desires to be converted to Judaism nowadays, he is asked: "What is your reason for desiring to be converted to Judaism? Are you not aware that Israel is broken down nowadays [under persecution] driven around [from one place to another], covered in mourning and tossed about, subject to so much affliction?" If he say: "I am aware of the fact and am not worthy even as they are," he is immediately accepted into Judaism. (Ib. b.) He is then informed concerning some of the light commandments, and some of the vigorous commandments [requiring self-denial], so that if upon such information, he desires to withdraw, he may do so. Because, R. Chelbo said: "Proselytes are as bad to Israel as a sore (Sappachath) is on the skin, for it is written (Is. 14, 1) And the strangers shall be joined unto them (V'nisspechu), and they shall attach themselves to the house of Jacob." He is then informed of the sin of [neglecting] Leket, Shik'cha, Peah, and Thites for the poor. Why these commandments? R. Chiya b. Aba said in the name of R. Jochanan: "Because the penalty of a Noahide for stealing a thing to the amount of even less than the smallest coin is death," [and thus upon observing that the poor take grain from his field, he might kill them for it.] The proposed proselyte is then informed concerning the punishment for [transgressing] the positive commandments; i.e., he is told: "You should be aware of the fact that prior to your conversion, when you had eaten fat [designated for the altar] you were not subject to Divine [capital] punishment; or if you had profaned the Sabbath [by doing any forbidden labor] you were not subject to the penalty of being executed by stoning; but henceforth if you eat the fat you will be subject to Divine [capital] punishment, and if you violate the Sabbath you will be subject to the penalty of stoning." Just as he is informed concerning the punishment [in the event of failure to observe] these commandments, so is he also informed concerning the reward [upon the fulfillment] of these commandments. He is told: "You shall be aware of the fact that the future world has been created for none else than the righteous, and that Israel nowadays is capable of withstanding the trials neither of much wealth nor of much retribution." No further [aversion] is to be used for him and no particular attention is to be paid [to his knowledge]. R. Elazar said: "What is the passage from whence we infer the above? It is written (Ruth 1, 18) When she thus saw that she was persisting to go with her, she left off speaking unto her. This means that Na'omi said unto Ruth: 'We are subject to Sabbatical limitations.' Whereupon the response came (Ib.) For whither thou goest, will I go. 'We are subject to the prohibition of privacy between a man and woman.' (Ib.) Where thou lodgest will I lodge. 'We are instructed to live in accordance with six hundred and thirteen commandments.' Whereupon Ruth replied (Ib) Thy people shall be my people. 'We are warned against idolatry.' (Ib) And thy God is my God. 'We are under jurisdiction of the court which has the right to execute us with either of the four kinds of capital punishment. (Ib.) Where thou diest shall I die. 'The court has even the right to bury one upon one of the two cemeteries it chooses.! (Ib) And there will I be buried, came again Ruth's reply. Immediately after this the passage said: When she thus saw that she was persisting to go," etc.

Rabba b. Huna said: "There is one great preference between an Israelite and a Proselyte. Concerning the Israelite the passage reads (Ez. 37, 27) And I will be their God, and they shall be My people, but concerning a Proselyte it is written (Jer. 30, 21) For who is this that has pledged his heart to approach unto Me?" R.Chelbo said:"Proselytes are as bad to Israel as a sore on the skin; for it is written (Is. 14, 1) And the stranger shall be joined unto them, and they shall attach (V'niss'pechu) themselves to the house of Jacob. It is written here [in the Text] V'niss'pchu, and it is written [concerning leprosy] the same expression (Lev. 14, 56) And for a swelling and for a rising (Sapachath)." R. Chama b. Chanina said: "At the time when the Holy One, praised be He, (Fol. 71) will purify the tribes He will commence with the tribe of Levi first, as it is said (Mal. 3, 3) And He will sit as a melter and purifier of silver; and He will purify the sons of Levi, and refine them as gold and silver, that they may offer unto the Lord an offering in righteousness." R. Joshua b. Levi said: "Impure families who joined Israel through the influence of their wealth, will be purified, as it is said (Mal. 3, 3) And He will sit as a melter and purifier of silver. What does the passage (Ib.) That they may offer unto the Lord an offering in righteousness, mean? Said R. Isaac: "Righteousness has the Lord done with Israel that every family which was mixed up beyond recognition is considered pure."