It is narrated from Sa'id bin al-Musayyib (may Allah have mercy on him) that 'Umar (may Allah be pleased with him) killed five or seven men in retaliation for one man whom they had killed deceitfully, and 'Umar (may Allah be pleased with him) said: "If all the people of Sana'a (a famous city in Yemen) had participated in this murder, I would have killed them all in retaliation."
Hadith Referenceمسند الإمام الشافعي / كتاب القتل والقصاص والديات والقسامة / 1611
Hadith Takhrijصحيح اخرجه البيهقي : 8 / 40 ، 41 ۔ وفى المعرفة السنن والآثار له (4831)۔ وعبدالرزاق (18073)، (18075) وابن ابى شيبة (27684)، (27685)۔