CC Antya 4.188

haridāsa kahe, — “tumi īśvara dayā-maya
tomāra gambhīra hṛdaya bujhana nā yāya
Word for word: 
haridāsa kahe — Haridāsa Ṭhākura said; tumi — You; īśvara — the Supreme Personality of Godhead; dayā-maya — merciful; tomāra — Your; gambhīra — deep; hṛdaya — heart; bujhana nā yāya — cannot be understood.
Translation: 
Haridāsa Ṭhākura said, “My dear Sir, You are the Supreme Personality of Godhead and are most merciful toward us. No one can understand what is within Your deeply affectionate heart.