The possuk begins with a ויו, to denote a continuation of the previous one. The Ohr Hachaim explains that this is a lesson to Klal Yisroel, that even if they are not converts from a foreign nation, they have the same obligations as the convert.
The possuk then continues with וְעָשָה פֶסַח – and he shall make a Pesach. The Ohr Hachaim explains that the Torah wants to limit this obligation to complete converts, who have accepted all Mitzvos on themselves. There are other foreigners who may live in Eretz Yisroel only if they accept on themselves the obligations against idol worship. These people are not considered Bnei Yisroel, and are not obligated to fulfill any Mitzvos. The Torah is saying that the obligation of this possuk is only for those foreigners that are ones who have the obligation of bringing a Korban Pesach.
Now the Possuk reads - וְכִי יָגוּר אִתְכֶם גֵר – If a foreign convert lives among you, וְעָשָה פֶסַח לַה – and he shall be of those who make a Korban Pesach to Hashem, כְחֻקַת הַפֶסַח וּכְמִשְפָטוֹ כֵן יַעֲשֶה - according to the statute of the Passover, and according to its ordinance, so shall he do. He must do the Mitzvah just like a Yisroel.
However, the Ohr Hachaim is not satisfied with this explanation, as nobody would ever mistake the word גֵר for anyone but a complete convert.
The Ohr Hachaim then continues to explain the possuk based on the Sifrei. Rabbi Shimon ben Elazar uses this possuk to learn the Halacha about a person who converts between the first Pesach and the second. Seeing as he could not bring the first Pesach, one may think he is obligated to bring the second one. The possuk says וּלְאֶזְרַח – and to a citizen. This tells us that the convert is akin to the naturally born citizen. Just like the citizen is obligated to bring a Pesach on the second opportunity if he did not bring on the first, so too must a convert.
The Ohr Hachaim explains that this Medrash relies on the extra ויו. Only those who were connected to the first Pesach bring the second one. Now, the possuk means וְכִּי יָגוּר אִּתְכֶם גֵר וְעָשָׂה פֶסַח 'לַה – If a convert shall join you, and he was someone who would bring a Korban Pesach, meaning he was someone who was obligated to - bring the Korban Pesach, כְחֻקַת הַפֶסַח וּכְמִשְפָטוֹ כֵן יַעֲשֶה – the rules of the Korban Pesach are for him to do.
The Ohr Hachaim then attempts another explanation. He begins by asking why the Torah needs to teach us this Halacha in the first place. Why would anyone think that a convert to Judaism would have a different set of rules regarding the Korban Pesach to any other Mitzvah in the Torah?
Why should a convert think he is exempt from this Mitzvah more than any other?
The truth is, the Sifrei writes that this possuk is the source for the Halacha that a convert is liable for all Mitzvos in the Torah. However, the question continues, why did the Torah choose Pesach to teach us that a convert is liable for all Mitzvos in the Torah?
The answer, writes the Ohr Hachaim, is that there is a good reason to believe that the Mitzvah of Korban Pesach is different to others. Korban Pesach serves as a reminder to what Hashem did for us when he redeemed us from Mitzrayim, and the convert was never in Mitzrayim. Just like a convert cannot read the Parsha of Bikkurim when he brings his new fruits to the Beis Hamikdash, because he cannot say, in truth, that Hashem promised to grant him a portion in Eretz Yisroel. This convert also needs a special command to bring a Korban Pesach. He did not live through an exodus from Mitzrayim, and neither did his ancestors. Why would we think that he is obligated in this Mitzvah?
The possuk says אִּתְכֶםוְכִי יָגוּר - if a convert shall be with you. Even though we can all see that he just joined our nation, he is like one of us and must bring a Korban Pesach.
The reason for this, and the meaning behind the convert’s obligation to bring a Korban Pesach is because he too has been redeemed on the night of Pesach. Although this redemption was not as obvious as that of ours, it is just as real. The source of holiness is equal, and when our forefathers were in Mitzrayim, the entire forces of holiness were trapped under their powers. If that source of holiness was never redeemed, the branches that are offshoots of that holiness would also never develop and be lost forever. When Klal Yisroel was removed from their clutches, the possibility of the convert’s arrival under the umbrella of Kedusha was born. The convert brings a Korban Pesach to celebrate this redemption.
He must bring his Korban הַפֶסַח כְחֻקַתlike all of the rules of the Korban Pesach. A person may think that the convert indeed has to celebrate, but how can he say the words ‘We were slaves to Par’oh in Egypt, and Hashem redeemed us’? Are these words not totally untrue?
The Torah tells such a person that his question is a mistake, and the convert needs to follow all of the Halachos of Pesach just like a born Yid.
Now that we have learned that the convert can keep the Halacha like everyone else, even though the words sound like they are untrue, the Torah has to tell us that the convert is obligated in every single Halacha. It is not merely a permission granted from Hashem for them to bring this Korban and celebrate in Hashem’s celebration, but an obligation that they must keep. To this, the Torah says חֻקָה אַחַת יִהְיֶה לָכֶם – You shall have one statute. This is an obligation, just like a born Yid.
