Acts 20: 26 – 31
26 Therefore I testify to you this day that I am innocent of the blood of all, 27 for I did not shrink from declaring to you the whole counsel of God. 28 Pay careful attention to yourselves and to all the flock, in which the Holy Spirit has made you overseers, to care for the church of God, which he obtained with his own blood. 29 I know that after my departure fierce wolves will come in among you, not sparing the flock; 30 and from among your own selves will arise men speaking twisted things, to draw away the disciples after them. 31 Therefore be alert, remembering that for three years I did not cease night or day to admonish every one with tears.
Jude 1: 3 – 4
3 Beloved, although I was very eager to write to you about our common salvation, I found it necessary to write appealing to you to contend for the faith that was once for all delivered to the saints. 4 For certain people have crept in unnoticed who long ago were designated for this condemnation, ungodly people, who pervert the grace of our God into sensuality and deny our only Master and Lord, Jesus Christ.
2 Tim 2: 15
15 Do your best to present yourself to God as one approved, a worker who has no need to be ashamed, rightly handling the word of truth.
Eph 4: 14
14 so that we may no longer be children, tossed to and fro by the waves and carried about by every wind of doctrine, by human cunning, by craftiness in deceitful schemes.
James 5: 19 – 20
19 My brothers, if anyone among you wanders from the truth and someone brings him back, 20 let him know that whoever brings back a sinner from his wandering will save his soul from death and will cover a multitude of sins.
The contention for truth against a different Jesus and a different gospel is of paramount importance because it concerns eternal life and death. But overbearing contention for any whim and fancy of tradition or matter of conscience is a different matter altogether and it belongs to an unrighteous critical spirit instead.
We are most uncharitable as Christians if we do nothing to bring back brothers who have wandered from the gospel truth and do not do our best to save their souls from death.