“Oh, the comfort — the inexpressible comfort of feeling safe with a person — having neither to weigh thoughts nor measure words, but pouring them all right out, just as they are, chaff and grain together; certain that a faithful hand will take and sift them, keep what is worth keeping, and then with the breath of kindness blow the rest away.”

A part of this passage appeared in The Best Loved Poems of the American People (1936) with the title "Friendship":
A Life for a Life (1859)
Context: Thus ended our little talk: yet it left a pleasant impression. True, the subject was strange enough; my sisters might have been shocked at it; and at my freedom in asking and giving opinions. But oh! the blessing it is to have a friend to whom one can speak fearlessly on any subject; with whom one's deepest as well as one's most foolish thoughts come out simply and safely. Oh, the comfort — the inexpressible comfort of feeling safe with a person — having neither to weigh thoughts nor measure words, but pouring them all right out, just as they are, chaff and grain together; certain that a faithful hand will take and sift them, keep what is worth keeping, and then with the breath of kindness blow the rest away.
Somebody must have done a good deal of the winnowing business this afternoon; for in the course of it I gave him as much nonsense as any reasonable man could stand...