Islam is a comprehensive religion. The Qur’an gives us the guidelines, but the details, terms and conditions we get from the Sunna (the hadith of Ahlulbayt). So I can’t just pick up the Qur’an and come up with my own understanding. I have to be an expert. I must know Arabic very will to understand the Qur’an. Then I must look at the Tafsir of those verses, and also the hadith of Ahlulbayt (a). That is why we follow scholars because they are experts in this field.