Sources
The duty to warn
In 1998 I heard, from my window in Nachaliel, Arab militias training at night with live fire. I told the people whose job it was: the rabbis, the chairman of the Knesset's Foreign Affairs and Defense Committee, the Prime Minister's Office. I was answered that it was "weddings." Then I went on without them. What obliged a man nobody appointed to go on? The sources answer.
ויקרא ה, א
וְנֶפֶשׁ כִּי־תֶחֱטָא וְשָׁמְעָה קוֹל אָלָה וְהוּא עֵד אוֹ רָאָה אוֹ יָדָע אִם־לוֹא יַגִּיד וְנָשָׂא עֲוֹנוֹ.
If a person sins: he heard the voice of an oath, and he is a witness, or he saw, or he knew; if he does not tell, he bears his iniquity.
The verse concerns a witness: one who saw or knew, and was adjured to tell. His silence the Torah counts as a sin that needs atonement. Not telling is a transgression.
ויקרא יט, טז; רמב"ם, הלכות רוצח ושמירת נפש א, יד
לֹא־תֵלֵךְ רָכִיל בְּעַמֶּיךָ לֹא תַעֲמֹד עַל־דַּם רֵעֶךָ אֲנִי ה׳.
Do not go about as a talebearer among your people; do not stand by the blood of your fellow: I am Hashem.
כָּל הַיָּכוֹל לְהַצִּיל וְלֹא הִצִּיל עוֹבֵר עַל לֹא תַעֲמֹד עַל דַּם רֵעֶךָ … אוֹ שֶׁשָּׁמַע עוֹבְדֵי כּוֹכָבִים אוֹ מוֹסְרִים מְחַשְּׁבִים עָלָיו רָעָה אוֹ טוֹמְנִין לוֹ פַּח וְלֹא גִּלָּה אֹזֶן חֲבֵרוֹ וְהוֹדִיעוֹ … עוֹבֵר עַל לֹא תַעֲמֹד עַל דַּם רֵעֶךָ.
Whoever can save and does not save transgresses "do not stand by the blood of your fellow" … or who heard that idolaters or informers were plotting harm against him or laying a trap for him, and did not reveal it to his fellow's ear and inform him … transgresses "do not stand by the blood of your fellow."
The same verse that forbids carrying tales forbids standing by, and the Rambam, in the Laws of the Murderer and the Preservation of Life, says whom the second half binds: one who sees his fellow drowning, or bandits or a wild animal coming at him, and could save him himself or hire others to, and does not; and one who heard that harm was being plotted against his fellow, or a trap laid for him, and did not reveal it to him. The second case is mine: a man who heard, from his own window, the training fire that the army and the Prime Minister's Office called "weddings," and knew the communities it was aimed at. The halacha says what he owes: to inform. It does not say which office he must hold first.
אבות ב, ה
וּבִמְקוֹם שֶׁאֵין אֲנָשִׁים, הִשְׁתַּדֵּל לִהְיוֹת אִישׁ.
And in a place where there are no men, strive to be a man.
Hillel is the speaker; the mishnah before it, in his name, begins "Do not separate yourself from the community." The two belong together. The man who strives to be a man where there are none does it inside the community, not outside it; he does not leave, and he does not wait. The mishnah does not say where there is no office. The offices were all in place. What was missing in the room was the man who would do the office's work, and the mishnah speaks to whoever is present.
שמות ב, יא–יב; ג, י
וַיִּפֶן כֹּה וָכֹה וַיַּרְא כִּי אֵין אִישׁ (ב, יב). וְעַתָּה לְכָה וְאֶשְׁלָחֲךָ אֶל־פַּרְעֹה (ג, י).
He turned this way and that, and saw that there was no man (2:12). And now go, and I will send you to Pharaoh (3:10).
Moshe went out to his brothers and saw their burdens; he saw an Egyptian striking a Hebrew; he looked this way and that, saw that there was no man, and acted. The next day he was asked who had made him a ruler and a judge (2:14). The sending came a chapter later, at the bush. The order in the text is the order of the sources above: he saw, there was no one, he acted, and the appointment, when it came, came afterward. Nothing in the text makes the act depend on the sending. The mishnah in Avot uses the verse's own word: no man, no men.
The objection
The strongest objection is this: public matters belong to the people appointed to them. The army has a chief of staff; the Knesset has a committee; the communities have a council; and a private man who writes to rabbis and newspapers about what the army should do is doing their job without their responsibility.
The objection is right about the order, and I kept the order. I warned the rabbis before I spoke to a newspaper; I briefed the committee chairman in person; the Report was put to four state bodies before it was printed. I did not go around any office. I went to it, I waited, and then I went on.
The sources above begin where the objection ends. "Do not stand by the blood of your fellow" has no clause that releases the one who saw once an office exists; the Rambam's cases all happen in a country that has courts and an army, and he rules on the bystander anyway. The mishnah speaks to the man in a room where the appointed are absent or silent.
Taken to its end, the objection says that a man who saw must keep silent as long as someone else is appointed, whatever the appointed one does. The Rambam rules the other way: the one who heard and did not inform has transgressed.
And when the Prime Minister's Office answered that the gunfire was "weddings," it did not say it had not been told. It had been told. That was its answer, and that was all it did.
What I do not claim
I am not a rabbi and I do not issue rulings. What I do is say what I saw and what they answered, and the Creator judges. My proposal on the vote puts each list's written commitments before a beit din that the list neither pays nor can appoint, and the ruling is the beit din's, not mine. I hold no office and belong to no party.