Placement of pauses and proportionate breath spans can produce a rhythm that does not depend on fixed poetic feet. Balance may be perceptible without unusual word order or a strained ending.
An extended verse may consist of several related phrases, while a brief verse can deliver an urgent warning with comparable force. In both cases, continuity of expression and the location of a pause contribute to the effect.
Rhetorical wisdom: the purpose is not to force every topic into verses of equal duration. Verse length serves the meaning and the occasion of the address.