Before we start, you may want to read איש בחטאו ימות, a source sheet by my brother, Shlomi Helfgot, for an introduction to this topic in Tanach.
(א) וַיֵּשֶׁב יִשְׂרָאֵל בַּשִּׁטִּים וַיָּחֶל הָעָם לִזְנוֹת אֶל בְּנוֹת מוֹאָב.(ו) וְהִנֵּה אִישׁ מִבְּנֵי יִשְׂרָאֵל בָּא וַיַּקְרֵב אֶל אֶחָיו אֶת הַמִּדְיָנִית ... (ז) וַיַּרְא פִּינְחָס בֶּן אֶלְעָזָר בֶּן אַהֲרֹן הַכֹּהֵן וַיָּקָם מִתּוֹךְ הָעֵדָה וַיִּקַּח רֹמַח בְּיָדוֹ. (ח) וַיָּבֹא אַחַר אִישׁ יִשְׂרָאֵל אֶל הַקֻּבָּה וַיִּדְקֹר אֶת שְׁנֵיהֶם...
(1) And Israel abode in Shittim, and the people began to commit harlotry with the daughters of Moab. (6) And, behold, one of the children of Israel came and brought unto his brethren a Midianitish woman... (7) And when Phinehas, the son of Eleazar, the son of Aaron the priest, saw it, he rose up from the midst of the congregation, and took a spear in his hand. (8) And he went after the man of Israel into the chamber, and thrust both of them through...
(יג) וְהָיְתָה לּוֹ וּלְזַרְעוֹ אַחֲרָיו בְּרִית כְּהֻנַּת עוֹלָם תַּחַת אֲשֶׁר קִנֵּא לֵאלֹהָיו וַיְכַפֵּר עַל בְּנֵי יִשְׂרָאֵל.
(13) and it shall be unto him, and to his seed after him, the covenant of an everlasting priesthood; because he was jealous for his God, and made atonement for the children of Israel.’
So far, this parasha has been averse to the idea of every person being responsible for their own self.
I'll try to explain the first two sources later, but right now, we'll look deeper for more examples of our responsibility law.
(ז) נֹצֵ֥ר חֶ֙סֶד֙ לָאֲלָפִ֔ים נֹשֵׂ֥א עָוֺ֛ן וָפֶ֖שַׁע וְחַטָּאָ֑ה וְנַקֵּה֙ לֹ֣א יְנַקֶּ֔ה פֹּקֵ֣ד ׀ עֲוֺ֣ן אָב֗וֹת עַל־בָּנִים֙ וְעַל־בְּנֵ֣י בָנִ֔ים עַל־שִׁלֵּשִׁ֖ים וְעַל־רִבֵּעִֽים׃
(7) keeping mercy unto the thousandth generation, forgiving iniquity and transgression and sin; and that will by no means clear the guilty; visiting the iniquity of the fathers upon the children, and upon the children’s children, unto the third and unto the fourth generation.’
(ב) וַיִּשְׁלְחוּ בְנֵי דָן מִמִּשְׁפַּחְתָּם חֲמִשָּׁה אֲנָשִׁים מִקְצוֹתָם אֲנָשִׁים בְּנֵי חַיִל מִצָּרְעָה וּמֵאֶשְׁתָּאֹל לְרַגֵּל אֶת הָאָרֶץ וּלְחָקְרָהּ וַיֹּאמְרוּ אֲלֵהֶם לְכוּ חִקְרוּ אֶת הָאָרֶץ וַיָּבֹאוּ הַר אֶפְרַיִם עַד בֵּית מִיכָה וַיָּלִינוּ שָׁם.(כז) וְהֵמָּה לָקְחוּ אֵת אֲשֶׁר עָשָׂה מִיכָה וְאֶת הַכֹּהֵן אֲשֶׁר הָיָה לוֹ וַיָּבֹאוּ עַל לַיִשׁ עַל עַם שֹׁקֵט וּבֹטֵחַ וַיַּכּוּ אוֹתָם לְפִי חָרֶב וְאֶת הָעִיר שָׂרְפוּ בָאֵשׁ.
(2) And the children of Dan sent of their family five men from their whole number, men of valour, from Zorah, and from Eshtaol, to spy out the land, and to search it; and they said unto them: ‘Go, search the land’; and they came to the hill-country of Ephraim, unto the house of Micah, and lodged there. (27) And they took that which Micah had made, and the priest whom he had, and came unto Laish, unto a people quiet and secure, and smote them with the edge of the sword; and they burnt the city with fire.
If an acquaintance of your's sins, then they are punished in full and you are punished partially for not stopping them. Full punishment can only be atoned for by the same person's repentance, but partial punishment can be atoned for by someone else.
Examples: Korah's son's lost all their possesions, but they still lived.
All the adulterers died, but also a portion of the innocent people in Bn"Y perished. Pinchas then went and did atonement, so no more of the innocents died, but the all the guilty people still passed away.
The Midianite men were punished in war because of what the women did, but the victory was partial and not complete.
(7) Nittai of Arbel said, Distance yourself from a bad neighbor, Do not befriend a wicked person, And do not despair of punishment.