SB 11.29.6
naivopayanty apacitim kavayas tavesa
brahmayusapi krtam rddha-mudah smarantah
yo ’ntar bahis tanu-bhrtam asubham vidhunvann
acarya-caittya-vapusa sva-gatim vyanakti
Translation:
O my Lord! Transcendental poets and experts in spiritual science could not fully express their indebtedness to You, even if they were endowed with the prolonged lifetime of Brahma, for You appear in two features — externally as the acarya and internally as the Supersoul — to deliver the embodied living being by directing him how to come to You.
Purport:
According to Srila Jiva Gosvami, Lord Krsna is ten million times more dear to a devotee than life itself. And according to Srila Visvanatha Cakravarti Thakura, even by rendering devotional service for the total duration of one thousand universal creations, a devotee cannot repay the debt he feels to the Lord for having awarded him loving service to the Lord’s lotus feet. The Lord appears within the heart as the Supersoul and externally both as the spiritual master and as His literary incarnation — the supreme Vedic knowledge of Bhagavad-gita and Srimad-Bhagavatam.