Question: Why is tawhīd the most important part of the uṣūl al-dīn?

Answer: Without tawhīd, none of Islam, let alone the uṣūl al-dīn, would make sense for all of Islam depends on the concept of the Absolute Oneness and Unity of God. 

Question: Are idols statues only?

Answer: No, our desires and egos can be idols as well for idols are simply entities which we enslave ourselves to.

Question: What is worship in Islam?

Answer: Worship in Arabic is ʿibāda, meaning to “enslave oneself to something.” From an Islamic perspective, we may worship objects like money, or people like our bosses if our hearts and minds are totally submitted to them.

Question: What is shirk?

Answer: Shirk is associating partners with Allah, either in creation, or in His attributes. For example, thinking that your parents are your sole providers is shirk since only Allah holds the attribute of sole Provider and Sustainer (al-Razzāq).

Question: Is tawhīd compatible with the Christian notion of the Trinity?

Answer: No, tawhīd means that God is absolutely one where He is not only one in essence, but is one person only and not three persons.