It is not always that easy for us to discover sectarian spirits which, indeed, infiltrated the Church from her very beginning, as the apostle Paul prophesied,
“I know that after my departure fierce wolves will come in among you, not sparing the flock; and from among your own selves will arise men speaking twisted things, to draw away the disciples after them.” (Acts 20:29-30 ESV)
Looking at the RCC, the distortion of Scripture is readily identifiable, since the Spirit of Christ indeed left their leaders, who adhered to the idea that (pagan) tradition could be at eye level with Scripture, long since. Also, adding self-invented sacraments and works to mere faith in Christ, who alone can save us from our sins, was definitely the outcome of listening to evil spirits.
But how can we discern evil spirits masquerading themselves as if coming from the Lord Jesus Christ right at the outset?