Sayyiduna Thabit bin Dhahak (may Allah be pleased with him) narrates from the Noble Prophet (peace and blessings be upon him) that he said: "Whoever swears falsely by a religion other than Islam, for example, says, 'If such and such happened, then I am a Jew,' then he will be as he said. And whoever kills himself with a weapon, he will be punished in Hell with that same weapon."