tabe tāra diśā sphure mo-nīcera hṛdaya
īśvara tumi,--ye karāha, sei siddha haya"
tabe—if you do so; tāra—of that; diśā—the process of writing; sphure—manifests; mo-nīcera—of someone lowborn like me; hṛdaya—in the heart; īśvara tumi—You are the Supreme Personality of Godhead; ye karāha—whatever You cause to do; sei siddha haya—that is perfectly done.
"If You would please manifest Yourself within my heart and personally direct me in writing this book, then, although I am lowborn, I may hope to be able to write it. You can do this because You are the Supreme Personality of Godhead Yourself, and whatever You direct is perfect."
Link to this page: https://prabhupadabooks.com/cc/madhya/24/327