Shiva Purana
ततस्स भगवाञ्छम्भुः कृपासिंधुर्महेश्वरः ॥ तदुपद्रवमाज्ञाय वृषरूपो बभूव ह॥ ५५॥
Then lord Śiva, the ocean of mercy, realising the havoc caused by the sons of Viṣṇu assumed the form of a bull.
english translation
tatassa bhagavAJchambhuH kRpAsiMdhurmahezvaraH ॥ tadupadravamAjJAya vRSarUpo babhUva ha॥ 55॥
hk transliteration by Sanscript