Shiva Purana
भूत्वा रुद्रश्च दुर्वासा ब्रह्मतेजोविवर्द्धनः ॥ चक्रे धर्मपरीक्षाञ्च बहूनां स दयापरः ॥ २८ ॥
Siva by becoming Durvāsas, the enhancer of Brahminical splendour, tested the piety of many people. He was merciful.
english translation
bhUtvA rudrazca durvAsA brahmatejovivarddhanaH ॥ cakre dharmaparIkSAJca bahUnAM sa dayAparaH ॥ 28 ॥
hk transliteration by Sanscript