Why did Imam attach great significance to internal struggle?

Imam Khomeini explained how sins corrupt the heart

Imam Khomeini through his books and works explained that not only are these illnesses unaccompanied by pain, but they also bring apparent pleasure. Meetings and sessions of backbiting are very warm and sweet! Love of the self and love of the world, which are the roots of all sins, are pleasurable.

Holly Prophetic Mission

Human soul inhabits sublime world, Imam Khomeini explained

Imam Khomeini through his theological works explained that the human soul inhabits another realm and another territory also, which is the world of the hidden and the sphere of the sublime world.

Imam Khomeini underlined sphere of sublime world

Imam Khomeini through his works has explained that the jihad al-nafs or the internal struggle is of great significance for all great religious thinkers and mystics.

Imam Khomeini, a sworn enemy of Zionism

One of the prominent member of Palestinian resistance group, Islamic Jihad

Imam Khomeini's exposition of Forty ahadith range broad area of ethical and spiritual topics

Imam Khomeini's selection and exposition of Forty ahadith range over a broad area of Islamic philosophy, ideology, ethics, metaphysics and spirituality.

Why did Imam Khomeini put emphasis on spiritual construction of nation?