CC Madhya 25.92

tāṅra sūtrera artha kona jīva nāhi jāne
ataeva āpane sūtrārtha kariyāche vyākhyāne
Word for word: 
tāṅra sūtrera artha — the meaning of Vyāsadeva’s Vedānta-sūtra; kona — any; jīva — living being; nāhi jāne — does not know; ataeva — therefore; āpane — personally; sūtra-artha — the meanings of the sūtras; kariyāche vyākhyāne — has described.
Translation: 
“The purport of the Vedānta-sūtra is very difficult for an ordinary person to understand, but Vyāsadeva, out of his causeless mercy, has personally explained the meaning.