There is one body, and one Spirit, even as ye are called in one hope of your calling; Ephesians 4:4
A big problem in the churches these days is the proclivity to confrontation. Ok, we're human, we like to fight. It's in our nature to stake out our territory, run with our group, and attack others who invade our space or dispute our statis quo. That is the reason why, over the last two thousand years more Christians have been persecuted by other christians than by any outside force. We destroyed each other during the inquisition, turned on each other during the crusades, and continue today in our sectarianism. This goes on within denominations, as in the Southern Baptist conflicts, and even within churches as pastors are relieved or congregants are driven out. Church battles destroy peoples faith as churches split, relationships crumble, and tempers heat into a we/them mentality.
The underground church rejects such internal feuding. The Body of Christ is one body with many members. We were put here to love and support each other. The enemy is quite capable of persecuting the church without any help from believers. We must stand together if we are to stand at all. The church survived the Roman persecution because it was united in Christ. The enemy seeks now to divide and conquer. A house divided against itself can not stand. We may not all agree, we are human, but together we stand.
This is not to say we should accept every diverse dogma. In these times, as in the past, there are doctrines of demons moving within the church. We must test the spirit by the word. We must stand against those who would injure the Body. For we wrestle not against flesh and blood, but against principalities, against powers, against the rulers of the darkness of this world, against spiritual wickedness in high places. Ephesians 6:12. We do not therefore fight against our brothers but against the powers of darkness that twist and corrupt the truth and propagate conflict.
It is our place to nurture and heal, not battle and destroy. Much like a nurse cares for her patient, we must love and care for those who suffer the wages of sin. We must gently lead those blinded by the darkness. We can not bring our brothers safely into our Fathers house through combat, nor can we drive them away without moving away ourselves.