Sayyiduna Sa'ib bin Yazid (may Allah be pleased with him) said that he heard Sayyiduna Uthman bin Affan (may Allah be pleased with him) while he was delivering a sermon on the pulpit of the Messenger of Allah (peace and blessings be upon him), saying that this is the month of your zakah. But Sa'ib did not name the month, nor did I ask him about it. He said: Sayyiduna Uthman (may Allah be pleased with him) said: Whoever among you owes a debt, let him pay off his debt; when your wealth has become free (of debt), then pay its zakah.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الزكاة / 7607