Shiva Purana
अंगमभ्यंतरं यागमग्निकार्यावसानकम् ॥ विधाय वा न वा पश्चाद्बहिर्यागं समाचरेत् ॥ २ ॥
With or without performing the internal worship which is its ancillary and which concludes with the rites in fire, one shall perform the external worship.
english translation
aMgamabhyaMtaraM yAgamagnikAryAvasAnakam ॥ vidhAya vA na vA pazcAdbahiryAgaM samAcaret ॥ 2 ॥
hk transliteration by Sanscript