Sayyiduna Jabir bin Abdullah (may Allah be pleased with him) said that the Messenger of Allah (peace and blessings be upon him) said: "Gatherings are a trust, except three kinds of gatherings, which are not a trust: 1. concerning the unlawful shedding of blood, 2. concerning fornication, 3. concerning unlawfully seizing someone's wealth."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الشهادات / 21162