Few things are more difficult than to help a Friend in matters which do not require the aid of Friendship, but only a cheap and trivial service, if your Friendship wants the basis of a thorough practical acquaintance.
 Henry David Thoreau, A Week on the Concord and Merrimack Rivers (1849). copy citation

Context

“But be the favoring gale That bears me on, And still doth fill my sail When thou art gone. I cannot leave my sky For thy caprice, True love would soar as high As heaven is. The eagle would not brook Her mate thus won, Who trained his eye to look Beneath the sun.
Few things are more difficult than to help a Friend in matters which do not require the aid of Friendship, but only a cheap and trivial service, if your Friendship wants the basis of a thorough practical acquaintance. I stand in the friendliest relation, on social and spiritual grounds, to one who does not perceive what practical skill I have, but when he seeks my assistance in such matters, is wholly ignorant of that one with whom he deals; does not use my skill, which in such matters is much greater than his, but only my hands.” source