Objection & response

Is Canon 15 optional or obligatory?

Whether the canon merely protects those who withdraw from a heresy preaching bishop, or positively commands withdrawal.

The objection, at its strongest

Canon 15 only shields those who separate from penalty; grammatically it protects an action, it does not command one. Separation is therefore permitted (δυνητικῶς), not required, and prudence may counsel awaiting a synod.

Why it is raised

The canon’s wording grants immunity (“are not subject to penalty… are worthy of honour”) rather than imposing a duty; and respected confessor canonists, together with the official Churches, read it this way.

Evidence for the objection

The clause is built as a protection for “those who separate,” not as an imperative addressed to all.
Canons 13 to 14 of the same council restrain separation from one’s bishop; canon 15 is the narrow exception, historically treated as extraordinary.
The tradition warns repeatedly against private judgment usurping the synod’s role.

Evidence against it

The heresy is already condemned: the canon presupposes a teaching “condemned by the holy Synods or Fathers,” so “before synodical judgment” concerns the deposition of the man, not a fresh verdict on the teaching, there is nothing further to await before withdrawing.
Other canons already command it: the Apostolic Canons (45, 46, 65) and Laodicea 33 forbid even praying with heretics, so Canon 15 protects the fulfilment of a standing duty rather than granting a new permission.
If communion with a heretic genuinely defiles (St Theodore the Studite), then remaining is spiritually harmful, which makes withdrawal a remedy, not a discretionary option.
The canon commends rather than merely excuses: those who withdraw are “worthy of honour” and have delivered the Church “from schism”, the language of a positive good.
The diachronic agreement of the Fathers: Maximus, Theodore, the Hagiorites and Mark of Ephesus all separated before conciliar verdicts, so the canon records a constant practice, not an optional indulgence.

A limited conclusion

Disputed

Read in isolation the clause protects rather than commands; read alongside the canons that already forbid communion with heresy, and with the Fathers who acted on it, the obligatory reading has the stronger case, which is the position this library takes. It remains genuinely contested: it turns on whether a given teaching is an “already condemned heresy” openly preached, and the official Churches and canonists such as Epiphanios Theodoropoulos read the canon permissively. The duty, where it binds, is to wall off, not to declare the wider Church graceless or found a rival hierarchy.