One who acts without knowledge is like one who travels off the path; and the one who acts without knowledge corrupts more than he rectifies. So seek knowledge in a way that does not harm your worship, and seek to worship [Allah] in a way that does not harm [your seeking of] knowledge. 
For verily, there were people (the Khawarij extremists) who sought to worship [Allah] but abandoned knowledge until they attacked the Ummah of Muhammad – Allah’s praise and peace be upon him – with their swords. But if they had sought knowledge, it would not have directed them to do what they did.

Al-Hasan Al-Basri – Allâh have mercy on him – Quoted by Ibn ‘Abd Al-Barr, Jami’ Bayân Al-’Ilm wa Fadlihi article 905.