Identify the speaker and context of the following excerpt from The Bhagavad Gita.

And like the ocean, day by day receiving
Floods from all lands, which never overflows;
Its boundary-line not leaping, and not leaving,
Fed by the rivers, but unswelled by those;-
So is the perfect one! to his soul’s ocean
The world of sense pours streams of witchery,
They leave him as they find, without commotion,
Taking their tribute, but remaining sea.