Ontology

These āyāt contain clear reference to the essentiality and importance of pure monotheism (tawḥīd) & submission/sincerity in worship (ʿibādah) and following the prophetic example (itibaʾ as-sunnah)
Our ontology is therefore deeply rooted in the teachings of the noble Qur’ān and the authentic Sunnah.

The whole life can, from an Islamic perspective, be summarised in the three essential questions (see above) that every person will be asked in the grave. Every aspect of life, every decision a persona makes, leads to that final examination.
References to the three questions can be found on: 
https://www.abuaminaelias.com/dailyhadithonline/2018/01/29/three-questions-grave/
https://www.abuaminaelias.com/dailyhadithonline/2019/01/16/pleased-allah-muhammad-islam/