Question: What is the furū al-dīn?

Answer: The most fundamental core practices of Islam 

Question: Telling the truth is not part of the 10 furūʿ al-dīn, does this mean it’s not important?

Answer: Telling the truth is part of the 7th furūʿ al-dīn, i.e. commanding the good. The furuʿ al-dīn are umbrella practices, they are general points that cover most Islamic practices. 

Question: What’s the difference between usūl al-dīn and furūʿ al-dīn?

Answer: The former are the fundamental core beliefs of Islam, the latter are its fundamental core practices. 

Question: If I don’t believe in practicing the furūʿ al-dīn, can I still be a Muslim?

Answer: If you do so knowing that Islam makes it obligatory, then no, you cannot be considered a Muslim. 

Question: Are the furūʿ al-dīn obligatory or recommended?

Answer: Obligatory.