Shiva Purana
तस्मादस्य प्रसादार्थं वाङ्मनोदोषवर्जिताः ॥ ध्यायंतश्शिवमेवैकं सदारतनयाग्नयः ॥ ४६ ॥
Therefore, in order to please Him, you should be free from faults in speech and mind. The fires with their wives and sons meditated on Lord Śiva alone.
english translation
tasmAdasya prasAdArthaM vAGmanodoSavarjitAH ॥ dhyAyaMtazzivamevaikaM sadAratanayAgnayaH ॥ 46 ॥
hk transliteration by Sanscript