“On every thorn, delightful wisdom grows, In every rill a sweet instruction flows.”

Source: Poems from the Pickering Manuscript (c. 1805), Auguries of Innocence, Line 123
Source: Songs of Experience

Source: Ars Poetica, or The Epistle to the Pisones (c. 18 BC), Line 343

To One Beloved.

Stanza 3.
1710s, Psalm 98 "Joy to the World!" (1719)

Bk. III, ch. 7.
1840s, Past and Present (1843)

Erst erfreuen, dann belehren.
Karl Friedrich Schinkel and Gustav Friedrich Waagen in "On the Purpose of the Berlin Gallery" [Über die Aufgabe der Berliner Galerie] (1828); occasionally attributed to von Humboldt, who had quoted Schinkel and Waagen in a report.
Misattributed

From an 1828 proposal "On the Purpose of the Berlin Gallery" (
This quotation is occasionally attributed to Wilhelm von Humboldt, which appears to be erroneous; von Humboldt had quoted Schinkel and Waagen in a report.

1840s, Essays: First Series (1841), Compensation
Context: Every excess causes a defect; every defect an excess. Every sweet hath its sour; every evil its good. Every faculty which is a receiver of pleasure has an equal penalty put on its abuse. It is to answer for its moderation with its life. For every grain of wit there is a grain of folly. For every thing you have missed, you have gained something else; and for every thing you gain, you lose something. If riches increase, they are increased that use them. If the gatherer gathers too much, nature takes out of the man what she puts into his chest; swells the estate, but kills the owner. Nature hates monopolies and exceptions.