Sayyiduna Abdullah bin al-Zubayr (may Allah be pleased with them both) and Sayyiduna Abdullah bin Amir bin Kurayz (may Allah be pleased with him) narrate that the Prophet (peace and blessings be upon him) said: "Whoever is killed defending his wealth is a martyr."
Al-Tabarani recorded it from both of them in al-Mu'jam al-Awsat. In al-Mu'jam al-Kabir he recorded it from Sayyiduna Abdullah bin al-Zubayr (may Allah be pleased with him) alone. Al-Bazzar recorded it likewise. Its chain contains Abdullah bin Mus'ab al-Zubayri, who is da'if (weak).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب قتال أهل البغي / 10467