Vivekachudamani 21

tadvairagyam jihasa ya darsana sravana dibhih | 
dehadi brahma paryante hyanitye bhogavastuni || 
(Sankaracarya's Vivekachudamani 21) 

The desire to give up all transient enjoyments gained through seeing, hearing, etc., and also experiences gained through equipment ranging from a mortal body to the form of Brahma is called 'detachment‘. 

The principles of knowledge and detachment are two important factors on the path of transcendental realization. The whole spiritual process leads to perfect knowledge of everything material and spiritual, and the results of such perfect knowledge are that one becomes detached from material affection and becomes attached to spiritual activities. Becoming detached from material things does not mean becoming inert altogether, as men with a poor fund of knowledge think. Naiṣkarma means not undertaking activities that will produce good or bad effects. Negation does not mean the negation of the positive. The negation of the nonessential does not mean the negation of the essential. Similarly, detachment from material forms does not mean nullifying the positive form. The bhakti cult is meant for the realization of the positive form. When the positive form is realized, the negative forms are automatically eliminated. Therefore, with the development of the bhakti cult, with the application of positive service to the positive form, one naturally becomes detached from inferior things, and he becomes attached to superior things. Similarly, the bhakti cult, being the super most occupation of the living being, leads him out of material sense enjoyment. That is the sign of a pure devotee. He is not a fool, nor is he engaged in the inferior energies, nor does he have material values. This is not possible by dry reasoning. It actually happens by the grace of the Almighty. In conclusion, one who is a pure devotee has all other good qualities, namely knowledge, detachment, etc., but one who has only knowledge or detachment is not necessarily well acquainted with the principles of the bhakti cult. Bhakti is the super most occupation of the human being.