Shiva Purana
शिवरूपादिचिंता या सा सेवा मानसी स्मृता ॥ जपादिर्वाचिकी सेवा कर्मपूजादि कायिकी ॥ ३५ ॥
The meditation on Śiva’s form is mental service. Repetition of mantras is verbal service. The rites of worship constitute the physical service.
english translation
zivarUpAdiciMtA yA sA sevA mAnasI smRtA ॥ japAdirvAcikI sevA karmapUjAdi kAyikI ॥ 35 ॥
hk transliteration by Sanscript