Shiva Purana
सर्वलोकपरित्राणं कर्तुमभ्युदितौ सदा ॥ स्वेच्छावतारं कुर्वंतौ स्वांशभेदैरनेकशः ॥ २५ ॥
They were always ready to save all the worlds. They incarnated at will in various ways by differing in their parts.
english translation
sarvalokaparitrANaM kartumabhyuditau sadA ॥ svecchAvatAraM kurvaMtau svAMzabhedairanekazaH ॥ 25 ॥
hk transliteration by Sanscript