I make known (gnōrizō). See note on 1Co 12:3 for this common verb. As if in reproach.
The gospel which I preached unto you (to euaggelion ho euēggelisamēn humin). Cognate accusative, “the gospel which I gospelized unto you.” Note augment ē after eu̇ like compound verb with preposition. Note repetition of relative (ho, en hōi, di hou, and tini like relative) without kai (and), asyndeton.