Śrīmad-Bhāgavatam · Text 3.6.36
Who is speaking and story frame
तथापि कीर्तयाम्यङ्ग यथामति यथाश्रुतम् ।
कीर्तिं हरे: स्वां सत्कर्तुं गिरमन्याभिधासतीम् ॥ ३६ ॥
tathāpi kīrtayāmy aṅga
yathā-mati yathā-śrutam
kīrtiṁ hareḥ svāṁ sat-kartuṁ
giram anyābhidhāsatīm
In spite of my inability, whatever I have been able to hear [from the spiritual master] and whatever I could assimilate I am now describing in glorification of the Lord by pure speech, for otherwise my power of speaking would remain unchaste.
Read Śrīla Prabhupāda's purport on Vedabase.io