Heresy

Teaching judged false, and the church's response to it.

Passages that substantially address this topic, in date order.

Didache 11.2Anonymous · ca. 50–150 (often ca. 100) · Reject teachers who undermine this teaching; welcome those who build it up.
Didache 16.3Anonymous · ca. 50–150 (often ca. 100) · In the last days false prophets will multiply and love will turn to hate.
Didache 6.1Anonymous · ca. 50–150 (often ca. 100) · Let no one lead you away from this teaching.
2 Clement 10.5Anonymous · ca. 100–150 · False teachers and their hearers will face double judgment.
2 Clement 9.1Anonymous · ca. 100–150 · The flesh will be judged and will rise.
To the Ephesians 16.2Ignatius of Antioch · ca. 110 (range ca. 105–135) · Corrupting the faith by false teaching is even worse than bodily sin.
To the Ephesians 17.1Ignatius of Antioch · ca. 110 (range ca. 105–135) · Christ's anointing brings incorruption; avoid the stench of the devil's teaching.
To the Ephesians 6.2Ignatius of Antioch · ca. 110 (range ca. 105–135) · The Ephesian church is orderly and free from heresy.
To the Ephesians 7.1Ignatius of Antioch · ca. 110 (range ca. 105–135) · Beware of false teachers who bear Christ's name but act unworthily.
To the Ephesians 9.1Ignatius of Antioch · ca. 110 (range ca. 105–135) · The Ephesians refused false teaching; they are stones raised into God's temple by the cross.
To the Magnesians 10.2Ignatius of Antioch · ca. 110 (range ca. 105–135) · Throw out the old leaven and be salted in Christ.
To the Magnesians 10.3Ignatius of Antioch · ca. 110 (range ca. 105–135) · It is absurd to confess Christ and live as a Jew; Judaism has found its fulfillment in Christianity.
To the Magnesians 11.1Ignatius of Antioch · ca. 110 (range ca. 105–135) · Hold firmly to the real birth, death, and resurrection of Christ under Pontius Pilate.
To the Magnesians 8.1Ignatius of Antioch · ca. 110 (range ca. 105–135) · Do not go back to Jewish practice, as if grace had not come.
To the Philadelphians 2.1Ignatius of Antioch · ca. 110 (range ca. 105–135) · Avoid division and follow the bishop as sheep follow their shepherd.
To the Philadelphians 2.2Ignatius of Antioch · ca. 110 (range ca. 105–135) · Unity protects the church from deceptive wolves.
To the Philadelphians 3.1Ignatius of Antioch · ca. 110 (range ca. 105–135) · Avoid false teachers; Ignatius found the church purified, not divided.
To the Philadelphians 3.3Ignatius of Antioch · ca. 110 (range ca. 105–135) · Following a schismatic excludes one from God's kingdom.
To the Philadelphians 6.1Ignatius of Antioch · ca. 110 (range ca. 105–135) · Do not listen to those who teach Judaism instead of Christ.
To Polycarp 3.1Ignatius of Antioch · ca. 110 (range ca. 105–135) · Polycarp must stand firm against false teachers, like an anvil under the hammer.
To the Smyrnaeans 2.1Ignatius of Antioch · ca. 110 (range ca. 105–135) · Christ truly suffered and truly rose, against those who say he only seemed to.
To the Smyrnaeans 4.1Ignatius of Antioch · ca. 110 (range ca. 105–135) · Avoid the false teachers entirely, but pray for their repentance.
To the Smyrnaeans 5.1Ignatius of Antioch · ca. 110 (range ca. 105–135) · Those who deny Christ's real suffering are themselves denied by him.
To the Smyrnaeans 5.2Ignatius of Antioch · ca. 110 (range ca. 105–135) · Denying that Christ had flesh is denying him completely.
To the Smyrnaeans 5.3Ignatius of Antioch · ca. 110 (range ca. 105–135) · Ignatius will not name the false teachers until they repent.
To the Smyrnaeans 6.2Ignatius of Antioch · ca. 110 (range ca. 105–135) · The false teachers show no love or care for those in need.
To the Smyrnaeans 7.1Ignatius of Antioch · ca. 110 (range ca. 105–135) · The docetists avoid the Eucharist because they deny it is Christ's flesh.
To the Smyrnaeans 7.2Ignatius of Antioch · ca. 110 (range ca. 105–135) · Avoid the false teachers and attend to the prophets and the gospel.
To the Trallians 10.1Ignatius of Antioch · ca. 110 (range ca. 105–135) · If Christ only seemed to suffer, Ignatius's martyrdom would be pointless.
To the Trallians 11.1Ignatius of Antioch · ca. 110 (range ca. 105–135) · False teachers are poisonous growths, not the Father's planting.
To the Trallians 6.1Ignatius of Antioch · ca. 110 (range ca. 105–135) · Feed only on Christian teaching and avoid heresy.
To the Trallians 6.2Ignatius of Antioch · ca. 110 (range ca. 105–135) · False teachers disguise poison with sweet words about Christ.
To the Trallians 7.1Ignatius of Antioch · ca. 110 (range ca. 105–135) · Stay close to God, the bishop, and the apostles' teaching.
To the Trallians 9.1Ignatius of Antioch · ca. 110 (range ca. 105–135) · Christ was truly born, truly suffered, and truly died.
To the Philippians 6.3Polycarp of Smyrna · ca. 110–135 · Serve Christ reverently as the Lord, apostles, and prophets taught, and avoid false brothers and hypocrites who mislead the unwary.
To the Philippians 7.1Polycarp of Smyrna · ca. 110–135 · Polycarp condemns those who deny that Christ came in the flesh, who deny the witness of the cross, and who twist the Lord's words to deny resurrection and judgment.
To the Philippians 7.2Polycarp of Smyrna · ca. 110–135 · Believers should hold to the teaching handed down from the beginning, watching in prayer and fasting as the Lord taught.