אבן העזר ג׳Even HaEzer 3

Se’if 1א׳

מִי שֶׁבָּא בַּזְּמַן הַזֶּה וְאָמַר: כֹּהֵן אֲנִי, אֵינוֹ נֶאֱמָן. וְאֵין מַעֲלִין אוֹתוֹ לִכְהֻנָּה עַל פִּי עַצְמוֹ, וְלֹא יִקְרָא בַּתּוֹרָה רִאשׁוֹן וְלֹא יִשָּׂא אֶת כַּפָּיו. הַגָּה: וְיֵשׁ אוֹמְרִים דְּנֶאֱמָן לִקְרוֹת בַּתּוֹרָה רִאשׁוֹן וְלִשָּׂא אֶת כַּפָּיו בַּזְּמַן הַזֶּה, שֶׁאֵין לָנוּ תְּרוּמָה דְּאוֹרָיְתָא שֶׁנָּחוּשׁ שֶׁמָּא יַעֲלוּ אוֹתוֹ לִתְרוּמָה (ב"י בְּשֵׁם הָרְמַ"ךְ). וְכֵן נוֹהֲגִין הָאִדָּנָא בְּכָל מָקוֹם שֶׁאֵין נוֹהֲגִין בִּתְרוּמָה בַּזְּמַן הַזֶּה וְלֵיכָּא לְמֵיחַשׁ לְמִידִי. וְלֹא יֹאכַל בְּקָדְשֵׁי הַגְּבוּל עַד שֶׁיִּהְיֶה לוֹ עֵד אֶחָד. אֲבָל אוֹסֵר עַצְמוֹ בִּגְרוּשָׁה וְזוֹנָה וַחֲלָלָה וְאֵינוֹ מִטַּמֵּא לְמֵתִים, וְאִם נָשָׂא אוֹ נִטְמָא לוֹקֶה. וְהַנִּבְעֶלֶת (לוֹ, אִם הִיא פְּסוּלֵי כְּהֻנָּה), סְפֵק חֲלָלָה. וְאִם הָיָה מֵסִיחַ לְפִי תֻּמּוֹ, נֶאֱמָן. כֵּיצַד, מַעֲשֶׂה בְּאֶחָד שֶׁהָיָה מֵסִיחַ לְפִי תֻּמּוֹ וְאָמַר: זָכוּר אֲנִי כְּשֶׁהָיִיתִי תִּינוֹק וְהָיִיתִי מֻרְכָּב עַל כְּתֵפוֹ שֶׁל אַבָּא, הוֹצִיאַנִי מִבֵּית הַסֵפֶר, הִפְשִׁיטוּנִי אֶת כֻּתָּנְתִּי וְהִטְבִּילוּנִי לֶאֱכֹל תְּרוּמָה לָעֶרֶב, וַחֲבֵרַי בְּדֵלִים מִמֶּנִּי וְהָיוּ קוֹרִין אוֹתִי: יוֹחָנָן אוֹכֵל חַלּוֹת; וְהֶעֱלָהוּ רַבֵּנוּ הַקָּדוֹשׁ לִכְהֻנָּה עַל פִּי עַצְמוֹ:

Someone who comes in our time and says, "I am a Cohen," we don't believe him and we don't raise him to Priesthood by his own word and he does not read (the) first (Aliyah) from the Torah and he does not raise his hands (for the Priestly blessing of the congregation). [Rama: But there are those who say that he is believed in order to read first from the Torah and to raise his hands (for the blessing) in our time since we don't have tithing from the Torah, about which we should be concerned that perhaps they would raise him (inappropriately) to (one who accepts holy) tithings. Thus, it is established as our universal custom not to accept tithings in our time and thus, we have no concern for this practice (of allowing him to read first from the Torah and raising his hands)] And we do not feed him from the kodshim of Israel unless there is at least one witness (that his is in fact a Priest). Nonetheless, he would make himself Assur to marry a divorcee a harlot or a Hallal and he would not be allowed to Metamei himself by the dead, but if he did marry or become tamei, he would suffer whiplashes and the woman whom he married (improperly) [who is for him pasula for Cohanim] a safek H'llala. If he was questioned in a way as to not reveal the purpose of the discussion (L'fi Tumo and reveals that he knows for sure that he is a Cohen) he would be believed. How is it possible to question him in a way that does not reveal the intent of the question? Ask him to recall the time when he was a child that "I would ride on my father's shoulders and he would remove me from school take off my clothes and Tovel me in the mikveh so I would eat Trumot after sunset and my friends separated from me and they would call me "Yochanan Who Eats Challah [Terumah]," Here, our holy sages would raise him to priesthood status by himself.

Se’if 2ב׳

הָיָה עֵד אֶחָד מֵעִיד עָלָיו, נֶאֱמָן לְהַאֲכִילוֹ בִּתְרוּמָה בַּזְּמַן הַזֶּה וְלִקְרוֹת בַּתּוֹרָה רִאשׁוֹן וְלִשָּׂא אֶת כַּפָּיו, וַאֲפִלּוּ אָבִיו נֶאֱמָן עָלָיו. וַאֲפִלּוּ מִשְּׁטָרוֹת מַעֲלִין לִכְהֻנָּה בַּזְּמַן הַזֶּה. כֵּיצַד, הֲרֵי שֶׁהָיָה כָּתוּב בַּשְּׁטָר: פְּלוֹנִי כֹּהֵן לָוָה מִפְּלוֹנִי מָנֶה, וְעֵדִים חֲתוּמִים עָלָיו, הֲרֵי זֶה בְּחֶזְקַת כֹּהֵן כְּכֹהֲנֵי זְמַן זֶה. וְכֵן מַעֲלִין מִנְּשִׂיאוּת כַּפַּיִם וּמִקְּרִיאָה בַּתּוֹרָה רִאשׁוֹן לִהְיוֹת כֹּהֵן כְּכֹהֲנֵי זְמַן זֶה. (וְיֵשׁ אוֹמְרִים דְּאִם חָתַם עַצְמוֹ: אֲנִי פְּלוֹנִי כֹּהֵן עֵד, מְהַנֵּי בַּזְּמַן הַזֶּה) (הָרַ"ן פֶּרֶק ב' דִּכְתֻבּוֹת):

If there was one witness that testified (that he is a Cohen), he is believed in order to feed him (the Cohen) tithes in these times, and he can read the first Aliyah from the Torah and to raise his hands (for the congregation). Even his father is believed for him and legal/court-documents can support his claim to Priesthood in these times, how so? if it was written in a court/legal-document he may show the document that was written with his name, Ploni Cohen borrowed from Ploni so much money and witnesses signed this document, thus, he will have the Hazaka of priesthood (on account of the document) like the Cohanim of this time. Hence, he may raise his hands and read First from the Torah and to be a priest like the priests of this time. [Rama: And there are those who say that even if he signed the document himself "I am Ploni the Cohen" this counts as a witness in these times.]

Se’if 3ג׳

אִם יָעִיד אֶחָד מֵהָאֲנוּסִים שֶׁאֶחָד מֵהֶם מֻחְזָק בִּכְהֻנָּה, מַעֲלִין אוֹתוֹ לִקְרוֹת בַּתּוֹרָה וְאֵין חוֹשְׁשִׁין שֶׁמָּא אִמּוֹ כּוּתִית:

If one of the "Anusim" (Jews who were forced to convert) bears witness that one of them is Muchzak (known by Hazaka) in priesthood, he may be raised to read (First Aliyah) from the Torah and we are not concerned that he is a Kuti (goy).