ἕνεκεν (heneken)
ἕνεκεν is an Ancient Greek form of ἕνεκα, meaning “on account of, for the sake of (+gen.)”. It is the preposition.
Found 425 times in the Ancient Greek texts on Socratos.
Where it is used
Apollonius Rhodius, Argonautica 4.364: σῶν ἕνεκεν καμάτων, ἵνα μοι σόος ἀμφί τε βουσὶν
Theocritus, Εἰδύλλια 29.37: νῦν μὲν κἠπὶ τὰ χρύσεα μᾶλʼ ἔνεκεν σέθεν
New Testament, Romans 8.36: καθὼς γέγραπται ὅτι Ἕνεκεν σοῦ θανατούμεθα ὅλην τὴν ἡμέραν, ἐλογίσθημεν ὡς πρόβατα σφαγῆς.
Source: Socratos (socratos.org), a free reader for Ancient Greek and Latin. Grammar from the Perseus Treebank and Morpheus; dictionary entries from Liddell-Scott-Jones, A Greek-English Lexicon (Perseus Digital Library, CC BY-SA). Counts are from the texts on Socratos.