Pesach Again?!

(ו) וַיְהִי אֲנָשִׁים אֲשֶׁר הָיוּ טְמֵאִים לְנֶפֶשׁ אָדָם וְלֹא יָכְלוּ לַעֲשֹׂת הַפֶּסַח בַּיּוֹם הַהוּא וַיִּקְרְבוּ לִפְנֵי מֹשֶׁה וְלִפְנֵי אַהֲרֹן בַּיּוֹם הַהוּא. (ז) וַיֹּאמְרוּ הָאֲנָשִׁים הָהֵמָּה אֵלָיו אֲנַחְנוּ טְמֵאִים לְנֶפֶשׁ אָדָם לָמָּה נִגָּרַע לְבִלְתִּי הַקְרִב אֶת קָרְבַּן יקוק בְּמֹעֲדוֹ בְּתוֹךְ בְּנֵי יִשְׂרָאֵל.

Numbers 9:6-7

(6) But there were certain men, who were unclean by the dead body of a man, so that they could not keep the passover on that day; and they came before Moses and before Aaron on that day. (7) And those men said unto him: ‘We are unclean by the dead body of a man; wherefore are we to be kept back, so as not to bring the offering of the LORD in its appointed season among the children of Israel?’

What is so unique about Pesach, that the people are asking for another chance to celebrate? (the Two positive מצוות)

במדבר ט׳:ט׳-י״ב

(ט) וַיְדַבֵּר יקוק אֶל מֹשֶׁה לֵּאמֹר. (י) דַּבֵּר אֶל בְּנֵי יִשְׂרָאֵל לֵאמֹר אִישׁ אִישׁ כִּי יִהְיֶה טָמֵא לָנֶפֶשׁ אוֹ בְדֶרֶךְ רְחֹקָה לָכֶם אוֹ לְדֹרֹתֵיכֶם וְעָשָׂה פֶסַח לַיקוק. (יא) בַּחֹדֶשׁ הַשֵּׁנִי בְּאַרְבָּעָה עָשָׂר יוֹם בֵּין הָעַרְבַּיִם יַעֲשׂוּ אֹתוֹ עַל מַצּוֹת וּמְרֹרִים יֹאכְלֻהוּ. (יב) לֹא יַשְׁאִירוּ מִמֶּנּוּ עַד בֹּקֶר וְעֶצֶם לֹא יִשְׁבְּרוּ בוֹ כְּכָל חֻקַּת הַפֶּסַח יַעֲשׂוּ אֹתוֹ.

Numbers 9:9-12

(9) And the LORD spoke unto Moses, saying: (10) ’Speak unto the children of Israel, saying: If any man of you or of your generations shall be unclean by reason of a dead body, or be in a journey afar off, yet he shall keep the passover unto the LORD; (11) in the second month on the fourteenth day at dusk they shall keep it; they shall eat it with unleavened bread and bitter herbs; (12) they shall leave none of it unto the morning, nor break a bone thereof; according to all the statute of the passover they shall keep it.

What are the differences between פסח and פסח שני?

What are the two Minhagim we do today to remember פסח שני?