If a living entity is developed in Kṛṣṇa consciousness and is merciful to others, and if his spiritual knowledge of self-realization is perfect, he will immediately attain liberation from the bondage of material existence.
In this verse the words dayā jīveṣu, meaning "mercy to other living entities," indicate that a living entity must be merciful to other living entities if he wishes to make progress in self-realization. This means he must preach this knowledge after perfecting himself and understanding his own position as an eternal servant of Kṛṣṇa. Preaching this is showing real mercy to living entities. Other types of humanitarian work may be temporarily beneficial for the body, but because a living entity is spirit soul, ultimately one can show him real mercy only by revealing knowledge of his spiritual existence.