Abu Dawud Book 18, Hadith Number 3590.

Narated By Abdullah ibn Umar : Yahya ibn Rashid said: We were sitting waiting for Abdullah ibn Umar who came out to us and sat. He then said: I heard the Apostle of Allah (PBUH) as saying: If anyone’s intercession intervenes as an obstacle to one of the punishments prescribed by Allah, he has opposed Allah; if anyone disputes knowingly about something which is false, he remains in the displeasure of Allah till he desists, and if anyone makes an untruthful accusation against a Muslim, he will be made by Allah to dwell in the corrupt fluid flowing from the inhabitants of Hell till he retracts his statement.