Why did Imam Khomeini maintain that Islamic system is obliged to undertake implementation of law?

Imam Khomeini sought to establish a model society based upon Islamic constitution and norms

In the course of its revolutionary developments under Imam Khomeini's guidance, the Iranian nation cleansed itself of the dirt and impurities accumulated during the tãghũtī past and purged itself of foreign ideological influences, thus returning to the authentic intellectual standpoints and world view of Islam. The mission of the Constitution is to realize the ideological objectives of the Islamic movement.

Imam Khomeini defined major objectives of holy scripture of Quran

Imam Khomeini used to attach special significance to reciting the holy scripture of Quran during holy month of Ramadan.

FM Zarif says resistance, referendum only viable solution to Palestine issue

Iran's Foreign Minister Mohammad Javad Zarif says the only viable solution to the decades-long Israeli-Palestinian conflict lies in taking the path of resistance and a popular vote, rather than the US-devised Middle East proposal that seeks to bolster Israeli hold on occupied land at the expense of Palestinian rights.

Imam Khomeini stressed moral and ethical approaches

Iranian nation's refusal to submit to bullying angers United States: Leader

Leader of the Islamic Revolution Ayatollah Seyyed Ali Khamenei says US leaders want Iran to abandon its “new message for the world” when they say the Islamic Republic should behave like a normal nation.

Islam only values virtue and piety, Imam Khomeini defined

Imam Khomeini, the late founder of the Islamic Republic once in a historic remarks defined the Quranic concepts of whoever is more pious and virtuous, has more value before God.

Human Nature from Viewpoint of Imam Khomeini

According to Imam Khomeini, curbing the instincts does not mean that their existence is not necessary. Instead, they must be endured. If it is so, there is no need then to preserve them, and the policy of eliminating them is the best one.