Midrasz do Liczb 19:10

And when a stranger shall sojourn with thee, and will keep the Passover to the Lord (ibid., v. 48). Does this mean that a stranger who is converted should offer a paschal sacrifice at the first opportunity? Yes, for Scripture says: And he shall be as one that is born in the land (ibid.). Therefore, just as one born in the land offers his sacrifice on the fourteenth day, so the proselyte should do so on the fourteenth day. If he is converted, however, between the two Passovers,¹¹That is, between the fifteenth day of Nisan and the fourteenth day of Iyar, the second Passover (Num. 19:10). he should offer the sacrifice on the second Passover. Let all his males be circumcised, and then let him come near and keep it (ibid.). This refers to the circumcision of free males and the circumcision of slaves, (the absence of which) prevents him (from offering the paschal sacrifice). If one wishes to perform the two rituals, the commandment of circumcision and the commandment of the paschal lamb, which takes precedence? Let all his males be circumcised is stated first, and that is followed by And let him come near and keep it. One law shall be to him that is home-born (ibid., v. 49). This verse declares that the home-born and the convert are equal with regard to all the commandments inscribed in the Torah.