When mention would be made, in the presence of Imaam Maalik (rahimahullah), of people who were responsible for fabricating and innovating things in Deen, Imaam Maalik (rahimahullah) would say the following, emphasizing the importance of holding onto the sunnah:

Hazrat ‘Umar bin ‘Abdul ‘Azeez (rahimahullah) said, “Rasulullah (sallallahu ‘alaihi wasallam) and the righteous Khulafaa (Khulafaa-e-Raashideen and the Sahaabah (radhiyallahu ‘anhum)) after him showed us the mubaarak sunnah and the way of Deen. In order to follow the Qur’aan Majeed, it will be necessary for one to hold firmly to the mubaarak sunnah of Rasulullah (sallallahu ‘alaihi wasallam). Practicing on the mubaarak sunnah is the only way to show complete obedience to Allah Ta‘ala and strengthen one’s Deen. After the mubaarak sunnah has been shown to us by Rasulullah (sallallahu ‘alaihi wasallam), the righteous Khulafaa and the Sahaabah (radhiyallahu ‘anhum), it is not permissible for any person to change the mubaarak sunnah practices or to think of introducing anything new in Deen that opposes these sunnah practices. The one who follows the mubaarak sunnah will be rightly guided, and the one who seeks the divine assistance of Allah Ta‘ala through following the mubaarak sunnah will receive the divine assistance of Allah Ta‘ala. The one who abandons the way of the mubaarak sunnah will be treading a path which is not the path of the believers. Allah Ta‘ala will leave him in the path he has chosen and enter him into Jahannum, and how evil an abode it is!”

When Imaam Maalik (rahimahullah) would quote this statement of Hazrat ‘Umar bin ‘Abdul ‘Azeez (rahimahullah), he would become extremely happy.

(Ad-Deebaaj-ul-Muzahhab 1/115-116)