Translation:The evening is long, the night is short.
It is a line from a German language short story.
I don't know if it is relevant but the characters in this particular short story are unusual or are in unusual circumstances.
The line has nice ring to it in English. Makes you wonder .....is it that the evenings seem really long or that it is the nights that seem really short. Or maybe both seem unusual for some reason. What is going on in the speaker's life that he feels this way?
It's case. "Die" is the feminine nominative. It's used when the noun is the subject of the sentence. "Die" is also the feminine accusative, which is the direct object, or the object that the action/verb is performed on. "Der" is used for feminine dative nouns, as well as masculine nominative nouns. The dative case is used for indirect objects, which is the object indirectly affected by the verb. Also, there are dative propositions, like "mit," "zu," etc., which automatically trigger the dative case, no matter what.
Ex.: "I gave the bottle to the mother."
'I' is the subject/nominative, 'the bottle' is the direct object/accusative, and 'the mother' is the indirect object/dative. In German, it would be:
"Ich habe der Mutter die Flasche gegeben."
(Note the switched word order: 'der Mutter/the mother' comes before 'die Flasche/the bottle.' Also, the 'to' in the English sentence doesn't need to be translated here since it's implied.)
Sorry for the long and detailed and complicated answer. German has a very intricate system. I'm just grateful that English got rid of this system a long time ago.