Here are two verses (one from the Srimad Bhagavatam; 1.2.13, and one from the Bhagavad-gita; 4.13) describing the importance of the varṇāśrama institution.
…the highest aim of life or the highest perfection of the institution of the varṇāśrama-dharma is to cooperate jointly for the satisfaction of the Supreme Lord.
By is Divine Grace A.C. Bhaktivedanta Swami PRabhupada
Canto One, Chapter 2, Text 13
ataḥ pumbhir dvija-śreṣṭhā
O best among the twice-born, it is therefore concluded that the highest perfection one can achieve by discharging the duties prescribed for one’s own occupation according to caste divisions and orders of life is to please the Personality of Godhead.
Human society all over the world is divided into four castes and four orders of life. The four castes are the intelligent caste, the martial caste, the productive caste and the laborer caste. These castes are classified in terms of one’s work and qualification and not by birth. Then again there are four orders of life, namely the student life, the householder’s life, the retired and the devotional life. In the best interest of human society there must be such divisions of life, otherwise no social institution can grow in a healthy state. And in each and every one of the abovementioned divisions of life, the aim must be to please the supreme authority of the Personality of Godhead. This institutional function of human society is known as the system of varṇāśrama-dharma, which is quite natural for the civilized life. The varṇāśrama institution is constructed to enable one to realize the Absolute Truth. It is not for artificial domination of one division over another. When the aim of life, i.e., realization of the Absolute Truth, is missed by too much attachment for indriya-prīti, or sense gratification, as already discussed hereinbefore, the institution of the varṇāśrama is utilized by selfish men to pose an artificial predominance over the weaker section. In the Kali-yuga, or in the age of quarrel, this artificial predominance is already current, but the saner section of the people know it well that the divisions of castes and orders of life are meant for smooth social intercourse and high-thinking self-realization and not for any other purpose.