1 John 1:5

Καὶ ἔστιν αὕτη ἡ ἀγγελία ἣν ἀκηκόαμεν ἀ αὐτοῦ καὶ ἀναγγέλλομεν ὑμῖν, ὅτι ὁ θεὸς φῶς ἐστιν καὶ σκοτία ἐν αὐτῷ οὐκ ἔστιν οὐδεμία

And this is the message which we have heard from him and we announce to you, that God is light and darkness is not in him at all.


 * αὕτη is the subject, this (fem. to agree with the predicate)
 * ἡ ἀγγελία is the predicate nominative with ἔστιν as the linking verb
 * ἣν relative pronoun which
 * ἀκηκόαμεν - perfect tense, 2P pl.
 * ἀναγγέλλομεν ὑμῖν - present indicative. We are announcing to you
 * οὐκ ἔστιν οὐδεμία - double negative for emphasis. In English, various ways of translating this, such as "not at all". οὐδεμία - "not even one bit"? Why feminine? To agree with σκοτία