Yahya bin Habban relates that he was with Sayyiduna Abdullah bin Umar (may Allah be pleased with them both), and Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) said to him: "When there is civil strife (fitnah), you people will consider killing to be nothing."
Ahmad recorded it; its narrators are the narrators of the Sahih, except Yahya bin Habban, whom Ibn Hibban declared thiqah (trustworthy). (Al-Haythami says:) I say: Some hadiths of this kind will come in the chapter concerning the trials (that are to occur).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الفتن - أعاذنا الله منها / 12282