“You shall listen to all sides and filter them from yourself.”
Whitman urges the reader not to borrow even his own viewpoint wholesale: other voices can be heard, but judgment still has to be worked through personally rather than accepted second-hand.
Source details
Leaves of Grass (1855), untitled first-edition poem later known as “Song of Myself,” printed page 14 (Wikisource scan page 20). The sentence follows Whitman’s warning against taking things at second or third hand and against looking only through another person’s eyes; the reviewed locator is edition-specific.