In which wrirting did Karl Marx say: "religion is the opiate of the
masses" and what was the sentence that followed?

Dear edison616,

That quotation by Karl Marx became widely known only in a shortened
version. The full original quote is:

"Religion is the sigh of the oppressed creature, the heart of a
heartless world, and the soul of soulless conditions. It is the opium
of the people."

(German original text: "Die Religion ist der Seufzer der bedrängten
Kreatur, das Gemüt einer herzlosen Welt, wie sie der Geist geistloser
Zustände ist. Sie ist das Opium des Volks.")

The next sentence is: "The abolition of religion as the illusory
happiness of the people is the demand for their real happiness."

(German original text: "Die Aufhebung der Religion als des
illusorischen Glücks des Volkes ist die Forderung seines wirklichen
Glücks.")

Karl Marx wrote that in the introduction to his writing "Zur Kritik
der Hegelschen Rechtsphilosophie" (Contribution to the Critique of
Hegel's Philosophy of Right), which he wrote in late 1843 or early
1844. It was first published in the February 1844 edition of the
Deutsch-Französische Jahrbücher. You can read the full text (in
English) here [1]:
http://www3.baylor.edu/~Scott_Moore/texts/Marx_Contr_Crit.html

Hope this answers your question!
Regards,
Scriptor


Sources:

[1] Baylor University: Contribution to the Critique of Hegel's
Philosophy of Right, by Karl Marx
http://www3.baylor.edu/~Scott_Moore/texts/Marx_Contr_Crit.html

Projekt Gutenberg: Zur Kritik der Hegelschen Rechtsphilosophie. Einleitung
http://gutenberg.spiegel.de/marx/heglrech/me01_378.htm

Search terms used:
marx religion opium quelle
://www.google.de/search?num=20&hl=de&newwindow=1&safe=off&c2coff=1&q=marx+religion+opium+quelle&btnG=Suche&meta=
"Zur Kritik der hegelschen Rechtsphilosophie" 
://www.google.de/search?num=20&hl=de&newwindow=1&safe=off&c2coff=1&q=%22Zur+Kritik+der+hegelschen+Rechtsphilosophie%22+&btnG=Suche&meta=
"it is the opium of the people"
://www.google.de/search?num=20&hl=de&newwindow=1&safe=off&c2coff=1&q=%22it+is+the+opium+of+the+people%22&btnG=Suche&meta=

Thanks for the quick reply....ed

I cannot imagine how this answer could have been improved. What would
have been needed to earn that fifth star, I wonder.

I'm amazed
- I always believed that it was 'religion is the opiate'

I'm pretty sure that the person who told us that is now fairly illustrious

Any chance that the German is ambiguous, eg: opium = opiate depending
on context (capitalization etc) ?