Church leaders had authority to -

Reprove, rebuke, and exhort

1 Thessalonians 5:14

And we urge you, brothers, warn those who are idle, encourage the timid, help the weak, be patient with everyone.

1 Timothy 6:3-5

3 If anyone teaches false doctrines and does not agree to the sound instruction of our Lord Jesus Christ and to godly teaching,

4 he is conceited and understands nothing. He has an unhealthy interest in controversies and quarrels about words that result in envy, strife, malicious talk, evil suspicions

5 and constant friction between men of corrupt mind, who have been robbed of the truth and who think that godliness is a means to financial gain.

Please read 2 Timothy 4.

Titus 1:13

This testimony is true. Therefore, rebuke them sharply, so that they will be sound in the faith

Titus 2:15

These, then, are the things you should teach. Encourage and rebuke with all authority. Do not let anyone despise you.

Titus 3:10

Warn a divisive person once, and then warn him a second time. After that, have nothing to do with him.

Maintain perfect unity

Romans 12:16

Live in harmony with one another. Do not be proud, but be willing to associate with people of low position. Do not be conceited.

1 Corinthians 1:10

I appeal to you, brothers, in the name of our Lord Jesus Christ, that all of you agree with one another so that there may be no divisions among you and that you may be perfectly united in mind and thought.

2 Corinthians 3:11

And if what was fading away came with glory, how much greater is the glory of that which lasts!