Amr bin al-Sharid narrates from his father (Sayyiduna al-Sharid, may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "When someone who has the means delays paying his debt, his honour becomes lawful (to speak against), and punishing him also becomes permissible."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب التفليس / 11280