It is narrated from Sayyiduna Amr bin Awf bin Milhah al-Muzani (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) said: "(It is not permissible) to slip away secretly (from the army), nor to embezzle the spoils of war; and whoever embezzles the spoils of war will come on the Day of Resurrection with what he embezzled."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 14088