“A faithful and good servant is a real godsend; but truly 'tis a rare bird in the land.”

Act V, scene iii
Love for Love (1695)

A buon servente guiderdon non pere.
Sonetto. (Poeti del Primo Secolo, Firenze, 1816, p. 104).
Translation reported in Harbottle's Dictionary of quotations French and Italian (1904), p. 239.

Words on the scaffold, attributed in The Essentials of Freedom : The Idea and Practice of Ordered Liberty in the Twentieth Century as explored at Kenyon College (1960) by Paul Gray Hoffman, p. 43
First reported in indirect speech in the Paris Newsletter (1535): « Apres les exhorta, et supplia tres instamment qu'ils priassent Dieu pour le Roy, affin qu'il luy voulsist donner bon conseil, protestant qu'il mouroit son bon serviteur et de Dieu premierement. » ("Afterward he exhorted them, and besought them very earnestly to pray to God for the King, that He should give him good counsel, protesting that he died his good servant, and God's first.")

Lectures http://www.neti.ee/cgi-bin/cache?query=wolfgang+drechsler&alates=0&url=http%3A%2F%2Fwww.tudengiportaal.ee%2Fpealeht%2Findex.php%3Fpage=3%26show=4,1,3,2%26out=1

Section 4, member 2, subsection 1, Purging Simples upward.
The Anatomy of Melancholy (1621), Part II

Source: Break-Out from the Crystal Palace (1974), p. 62

Commonly quoted on the internet, and also in recent books such as Planetary Survival Manual by Matthew Stein (2000), p. 51.
Stein's book is the earliest published source located with that precise version of the quote, but the quote can be found in earlier Usenet posts such as this one from 1995 http://groups.google.com/group/rec.arts.ascii/msg/d9f6ec3887950a0d?hl=en, and other published variants of the quote using the words "sacred gift" can be found earlier. A Google Books search http://books.google.com/advanced_book_search?q=%22sacred+gift%22+einstein with the date range restricted to 1900-1990 shows only a handful in the 1980s and 1970s, and several of them attribute it to The Metaphoric Mind by Bob Samples (1976), which also seems to be the earliest published variant. Samples does not provide an exact quote, but writes on p. 26: "Albert Einstein called the intuitive or metaphoric mind a sacred gift. He added that the rational mind was a faithful servant. It is paradoxical that in the context of modern life we have begun to worship the servant and defile the divine." It seems as if the last sentence about worshipping the servant is just Samples' own comment (though in later variants it became part of the supposed quote), while the earlier sentences only paraphrase something that Samples claims Einstein to have said. Einstein had many quotes about the value of intuition and imagination, but the specific word "gift" can be found in a comment remembered by János Plesch in the section Attributed in posthumous publications, "When I examine myself and my methods of thought I come to the conclusion that the gift of fantasy has meant more to me than my talent for absorbing positive knowledge." So, Bob Samples might have been paraphrasing that comment. Likewise Einstein had a number of quotes about the intellect being secondary to intuition, but the language of the intellect "serving" can be found in a quote from the Out of My Later Years (1950) section, "And certainly we should take care not to make the intellect our god; it has, of course, powerful muscles, but no personality. It cannot lead, it can only serve; and it is not fastidious in its choice of a leader."
Misattributed

William J. Baumol. "Predation and the Logic of the Average Variable Cost Test." Journal of Law and Economics, Vol. XXXIX, April 1996, p. 51.