Thabit bin al-Dahhak (may Allah be pleased with him) says that the Messenger of Allah (peace and blessings be upon him) said: "The believer is not obliged to fulfil a vow over what he does not own; cursing a believer is like killing him; whoever kills himself with something will be punished with it on the Day of Resurrection; and whoever falsely swears by a religion other than Islam is as he said."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الأيمان / 19834