The young Christian, having seen that a great line exists between the believer and the unbeliever, being the born again and the dead (1 Pet. 1:3; Eph. 2:1-3) often seeks to demarcate the right and the false with greater ferocity and less wisdom than meets the case. Too easily, the young Christian, diligent for the honor of the Church and the purity of the Gospel, tilts at all comers and checks everything by the narrowest point of his own congregation.
It takes great maturity to distinguish between the time to confront and the time welcome with differences. The first instruction of Paul to Timothy reads:
3 As I urged you when I was going to Macedonia, remain at Ephesus so that you may charge certain persons not to teach any different doctrine, 4 nor to devote themselves to myths and endless genealogies, which promote speculations rather than the stewardship from God that is by faith. 5 The aim of our charge is love that issues from a pure heart and a good conscience and a sincere faith. 1 Timothy 1:3–5 (ESV)
Note that Paul laid the instruction upon Timothy a man who had traveled with and had learned under Paul for something likely more than 15 years (Paul meets Timothy during the Second Missionary Journey (A.D. 49-52), Acts 16:1-3; and writes 1 Timothy somewhere around A.D. 65). Paul also warns Timothy about those who senselessly fight about words:
22 So flee youthful passions and pursue righteousness, faith, love, and peace, along with those who call on the Lord from a pure heart. 23 Have nothing to do with foolish, ignorant controversies; you know that they breed quarrels. 24 And the Lord’s servant must not be quarrelsome but kind to everyone, able to teach, patiently enduring evil, 25 correcting his opponents with gentleness. God may perhaps grant them repentance leading to a knowledge of the truth, 26 and they may come to their senses and escape from the snare of the devil, after being captured by him to do his will. 2 Timothy 2:22–26 (ESV)
To distinguish danger from difference takes wisdom: in particular it takes understanding whether one truly holds to Jesus or merely holds to an opinion.
John gave Jesus the opportunity to make such a distinction in Mark 9:38-41:
38 John said to him, “Teacher, we saw someone casting out demons in your name, and we tried to stop him, because he was not following us.” 39 But Jesus said, “Do not stop him, for no one who does a mighty work in my name will be able soon afterward to speak evil of me. 40 For the one who is not against us is for us. 41 For truly, I say to you, whoever gives you a cup of water to drink because you belong to Christ will by no means lose his reward. Mark 9:38–41 (ESV)
One might be surprised to find John as the one marking off the difference. Bruce explains that John at this point is not what John will become:
John, it will be observed, does not disclaim joint responsibility for the high-handed proceeding he relates, but speaks as if the twelve had acted unanimously in the matter. It may surprise some to find him, the apostle of love,[14.24 consenting to so uncharitable a deed; but such surprise is founded on superficial views of his character, as well as on ignorance of the laws of spiritual growth. John is not now what he will be, but differs from his future self, as much as an orange in its second year differs from the same orange in its third final year of growth. The fruit of the Spirit will ultimately ripen in this disciple into something very sweet and beautiful; but meantime it is green, bitter, and fit only to set the teeth on edge. Devoted in mind, tender and intense in his attachment to Jesus, scrupulously conscientious in all his actions, he is even now; but he is also bigoted, intolerant, ambitious. Already he has played the part of a very high churchman in suppressing the nonconforming exorcist; ere long we shall see him figuring, together with his brother, as a persecutor, proposing to call down fire from heaven to destroy the enemies of his Lord; and yet again we shall find him, along with the same brother and their common mother, engaged in an ambitious plot to secure those places of distinction in the kingdom about which all the twelve have lately been wrangling.