Shiva Purana
मन्त्रकुम्भे च विन्यस्य मन्त्रं मन्त्रविशारदः ॥ कृत्वा मुद्रादिकं सर्वं मन्त्रयागं समाचरेत् ॥ २१ ॥
The expert in chanting mantras placed the mantra in a mantra pot After performing all the mudras and other rituals, one should perform the mantra-yajña.
english translation
mantrakumbhe ca vinyasya mantraM mantravizAradaH ॥ kRtvA mudrAdikaM sarvaM mantrayAgaM samAcaret ॥ 21 ॥
hk transliteration by Sanscript