Srimad Bhagavatam Canto 05, Chapter 25, Text 10

SB 5.25.10

murtim nah puru-krpaya babhara sattvam
 samsuddham sad-asad idam vibhati tatra
yal-lilam mrga-patir adade ’navadyam
 adatum svajana-manamsy udara-viryah
 
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
 
This manifestation of subtle and gross matter exists within the Supreme Personality of Godhead. Out of causeless mercy toward His devotees, He exhibits various forms, which are all transcendental. The Supreme Lord is most liberal, and He possesses all mystic power. To conquer the minds of His devotees and give pleasure to their hearts, He appears in different incarnations and manifests many pastimes.
 
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
 
Srila Jiva Gosvami has translated this verse as follows. “The Supreme Personality of Godhead is the cause of all causes. It is by His will that gross and subtle ingredients interact. He appears in various incarnations just to please the hearts of His pure devotees.” For example, the Supreme Lord appeared in the transcendental incarnation of Lord Varaha (the boar) just to please His devotees by lifting the planet earth from the Garbhodaka Ocean.
Srimad Bhagavatam Canto 05, Chapter 25, Text 09
Srimad Bhagavatam Canto 05, Chapter 25, Text 11