CC Antya 1.139
vidhātrī siddhārthān hari-guṇa-mayī vaḥ kṛtir iyam
pulindenāpy agniḥ kim u samidham unmathya janito
hiraṇya-śreṇīnām apaharati nāntaḥ-kaluṣatām
abhivyaktā — manifested; mattaḥ — from me; prakṛti — by nature; laghu-rūpāt — situated in a lower position; api — although; budhāḥ — O learned devotees; vidhātrī — which may bring about; siddha-arthān — all the objects of perfection; hari-guṇa-mayī — whose subject matter is the attributes of Kṛṣṇa; vaḥ — of you; kṛtiḥ — the poetic play known as Vidagdha-mādhava; iyam — this; pulindena — by the lowest class of men; api — although; agniḥ — a fire; kim u — whether; samidham — the wood; unmathya — rubbing; janitaḥ — produced; hiraṇya — of gold; śreṇīnām — of quantities; apaharati — vanquishes; na — not; antaḥ — inner; kaluṣatām — dirty things.
“ ‘O learned devotees, I am by nature ignorant and low, yet even though it is from me that the Vidagdha-mādhava has come, it is filled with descriptions of the transcendental attributes of the Supreme Personality of Godhead. Therefore, will not such a literature bring about the attainment of the highest goal of life? Although its wood may be ignited by a low-class man, fire can nevertheless purify gold. Similarly, although I am very low by nature, this book may help cleanse the dirt from within the hearts of the golden devotees.’ ”
This verse is Vidagdha-mādhava 1.6.