tesam evanukampartham
aham ajnana-jam tamah
nasayamy atma-bhava-stho
jnana-dipena bhasvata

"To show them special mercy, I, dwelling in their hearts, destroy with the shining lamp of knowledge the darkness born of ignorance."

Tesam = those without expecting any reward perform Bhakti, anukampena = with [the Lord's] sympathetic blessings, [ kampam = tremour or vibration, anu kampam = sympathise or sympathetic vibration], eva = by that alone, as why his blessings are there can not be understood; He shows mercy or sympathy, because we are His children. Atma = [in such a devotee's] mind, bhava stha = [the Lord] establishes firmly His image and His auspicious qualities, jnana deepam = light of knowledge [about the Lord], bhasvata = illuminates brightly. The Lord ensures that in the mind of these devotees, the knowledge about Him, His image and His auspicious qualities are brightly illuminated. This removes darkness. That is this dispels the impurities Arjuna thought in his doubt. The Lord lights up brilliantly His qualities and image, and in that illumination, all the impurities and darkness are cleared. Aham = I [Sri Krishna], tama = darkness, ajnana = ignorance or infinite time karma and the consequent papa, jam = originated, nasayami = destroy. The Lord destroys the desire for worldly matters, by illuminating in the mind His image and His auspicious qualities. He does it because of the love or Sympathy for the devotee.