My thanks to Fr Richard John Neuhaus for this reference which is surely helpful in our assessment of Pope Honorius–who had the misfortune to go down in history as having his (possibly) monothelitist opinion condemned by the Sixth Ecumenical Council. It comes from a letter by Pope Pelagius II (d. 590 — before Honorius, so it establishes something a point of view against which Honorius’ theological slip up may be evaluated) in which he is explaining to the Bishops in the West why he changed his opinion on a certain matter:
Dear Brethren, do you think that to Peter, who was reversing his position, one should have replied: We refuse to hear what you are saying since you previously taught the opposite? If in [this] matter one position was held while truth was being sought and a different position was adopted after truth had been found, why should a change of position be imputed a crime to this See which is humbly venerated by all in the person of its founder?
The application is that Honorius made his comment about Christ having only one will in a letter to Sergius BEFORE the Church had made a definitive pronouncement on the matter. While the theology which is reflected in his opinion was later found to have been heretical, he could not at the time have been (and was not later) considered to be a heretic. And of course, as Pope Pelagius points out, even Peter himself was corrected by Paul with regard to the role of the Jewish law in the Christian faith. The point at issue is that, when corrected, Peter (or his successor as in later history) changed his opinion and adopted and continued to defend the truth which “had been found”.