The ''word '''Ecthesis''''' (, from the Greek εκθεσις, εκθεσις meaning a "statement of faith") , was used famously as the title of a thesis by emperor [[heresy|hereticalHeraclius]] formula issued in 638 by Emperor to state a [[Heracliusheresy|heretical]]formula forbidding the mention of "energies".

It forbid forbade the mention of "energies," either one or two, in the person of [[Jesus Christ]]. It also asserted that the two natures of Christ were united in a single will (i.e.g., [[Monothelitism]]). It had been drafted earlier in 638 by Patriarch [[Sergius I of Constantinople]] after consultation with Pope [[Honorius I of Rome|Honorius of Rome]]. It was accepted by synods held in the Imperial capital, but quickly repudiated by Heraclius as well as Honorius' two successors (Popes Severinus and John IV).

The text of the ''Ecthesis'' is preserved in the ''Acta'' of the [[Lateran Council|Lateran Council of 649]].