“…idolatry, sorcery, hatred, contentions, jealousies, outbursts of wrath, selfish ambitions, dissensions, heresies…”
“Heresy” is self–willed opinion in that stands in opposition to truth. We could translate this word “sects.” The word “heresies” means act of taking. This is a sin of one’s chosen selfish opinion.
In context, “heresy” is an opinion that varies from the truth of the Word. The idea is to choose doctrine that opposes Scripture. These people fall into heretical sects and parties causing dissension and factions with those who hold to truth (1 Corinthians 11:19).
Heresy is the sin of forming doctrinal cliques.
Heresy is sin toward the Word of God. People love to separate others from their groups so that they follow their unique doctrines instead of constituted leadership of sound organizations.
Christianity is replete with people who develop their own unique doctrines and try to siphon others away from existing Bible-believing organizations. Anyone who holds opinions opposite to the Word is sectarian. We commit heresies when we hold viewpoints in opposition to the Word of God.
Cliques break up the unity of the church. They shut others out of their doctrinal circle. It is one thing to stand for truth but it is another thing to form novel doctrine because you think that you have come to an understanding of truth no one else has discovered yet. This is an area where we should carefully examine ourselves. We want to be true to truth, but truth should unite Christians, not divide them.