Verse 16

हरिं परमया भक्त्या जगद्विभवभव्यया ।मनसा पूजयामास प्रह्रादोऽन्तःपुरे पतिम्

In plain words

with supreme bhakti, resplendent with the glory of the world, Prahrāda worshipped Hari, the Lord, in his mind, in the inner chamber.