It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that the Prophet (peace and blessings be upon him) said: "Whoever helps falsehood in order to refute the truth with his falsehood, the protection of Allah and of His Messenger (peace and blessings be upon him) is free of him."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 11490