Sayyiduna Ghudayf bin al-Harith al-Thumali (may Allah be pleased with him) narrates that the Prophet (peace and blessings be upon him) said: "Whenever any nation introduces an innovation into its religion after its Prophet, it (that nation) loses a Sunnah like it."
Tabarani recorded it in al-Mu'jam al-Kabir; its chain contains Abu Bakr bin Abi Maryam, who is munkar al-hadith (his narrations are rejected).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب العلم / 893