Sayyiduna Jabir bin Abdullah (may Allah be pleased with them both) narrates that he heard the Messenger of Allah (peace and blessings be upon him) say: "Let no one swear a false oath near this minbar of mine, even if it is over a green tooth-stick, or else he has taken his seat in Hell," or: "Hell has become obligatory for him."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الشهادات / 20692