I don't think writing, in the Ancient Greek world, had the power it has in this modern printing society. The role of spreading ideas and news was on the poets and heralds. So how about a phrase that goes like "a herald(or messaenger) is worth an army"
[face=SPIonic]a)/ggeloj a)/cioj strato/pedou.[/face]
or, more visually(???), and with repeating -ng-g at the both ends:
[face=SPIonic]a)/ggeloj a)/cioj fa/laggoj[/face]