Progress is of two kinds: material and spiritual. The former
is attained through observation of the surrounding existence and constitutes
the foundation of civilization. Spiritual progress is through the breaths of
the Holy Spirit and is the awakening of the conscious soul of man to perceive
the reality of Divinity. Material progress ensures the happiness of the human
world. Spiritual progress ensures the happiness and eternal continuance of the
soul.
(‘Abdu’l-Baha, "The Promulgation of Universal Peace: Talks Delivered
by 'Abdu'l-Bahá during His Visit to the United States and Canada in 1912")
