SB 1.5 - Activities mixed with bhakti
Whatever work is done in this life for the satisfaction of the Lord is called bhakti yoga or transcendental loving service to the Lord, and what is called knowledge becomes a concomitant factor. The general understanding is that by performing karma according to scriptures one develops knowledge for self realization. Some consider bhakti yoga to be another form of karma. Factually bhakti yoga is above both karma and jñāna. The kriyā-yoga or karma-yoga as recommended by Nārada to Vyāsa is simply to satisfy the Lord. One has to be purified before one can go back to Godhead.
That karma which is offered to the Lord causes purification to the level of sattva-guṇa. That knowledge generated from karma which is without desire and which is pleasing to the Lord because of being offered to the Lord is endowed with bhakti, since jñāna devoid of bhakti will not give liberation. This is bhakti-miśra-jñāna. When work is done to satisfy the Lord, the performer becomes purified from material affection. Then one attains spiritual knowledge. Therefore, knowledge is dependent on work done for the Lord. Other knowledge, being devoid of bhakti yoga cannot lead one back to the kingdom of God. A devotee engaged in hearing and chanting of the glories of the Lord becomes spiritually enlightened.