Within Vasudeva’s heart, affection for his son and knowledge of the Supreme Lord’s transcendental nature both awakened. In the beginning Vasudeva thought, “Such a beautiful child has been born, but now Kaḿsa will come and kill Him.” But when he understood that this was not an ordinary child but the Supreme Personality of Godhead, he became fearless.
This is very good example for all of us. It is explained in the Srimad Bhagavatam that when one performs devotional service in material life karma yoga means to work without being attached to the fruit. But in spiritual life it is said in Bhagvatam that when you perform devotional service certain benefits, certain fruits will come from that action of devotional service you should not be attached to that, you should understand it is for Krishna’s enjoyment.