"Have nothing to do with stupid, senseless controversies; you know that they breed quarrels. And The Lord's servant must not be quarrelsome but kindly to every one, an apt teacher, forbearing, correcting his opponents with gentleness. God may perhaps grant that they will repent and come to know the Truth, and they may escape from the snare of the devil, after being captured by him to do his will." (2 Timothy 2:23-26 RSV)
What's An Argument?
A debate can be defined as "a discussion in which reasons are advanced for and against some proposition or proposal," while a quarrel could be defined as "a rude altercation." The word argument can be used for either.
Christians are expected to debate, or argue, in a polite and respectful way, with those who ask questions, or even those who wish to challenge Biblical teachings with their own beliefs:
"Now a Jew named Apollos, a native of Alexandria, came to Ephesus. He was an eloquent man, well versed in the Scriptures ... for he powerfully confuted the Jews in public, showing by the Scriptures that the Christ was Jesus." (Acts 18:24,28 RSV)
"Always be prepared to make a defense to any one who calls you to account for the hope that is in you, yet do it with gentleness and reverence; and keep your conscience clear, so that, when you are abused, those who revile your good behavior in Christ may be put to shame. For it is better to suffer for doing right, if that should be God's will, than for doing wrong." (1 Peter 3:15-17 RSV)
But Christians must not quarrel, with others, or among themselves:
"Remind them of this, and charge them before The Lord to avoid disputing about words, which does no good, but only ruins the hearers. Do your best to present yourself to God as one approved, a workman who has no need to be ashamed, rightly handling the word of Truth. Avoid such Godless chatter, for it will lead people into more and more ungodliness, and their talk will eat its way like gangrene." (2 Timothy 2:14-17 RSV)
"If any one teaches otherwise and does not agree with the sound words of our Lord Jesus Christ and the teaching which accords with Godliness, he is puffed up with conceit, he knows nothing; he has a morbid craving for controversy and for disputes about words, which produce envy, dissension, slander, base suspicions, and wrangling among men" (1 Timothy 6:3-5 RSV)
For most of us, it's not easy to be insulted and do nothing, when every fiber of our being wants to retaliate with everything that we can muster, but it's the basis of Christ's famous "turn the other cheek" (i.e. don't offend someone who's being offensive) teaching. Apart from the "being civilized" aspect of it, there is also the practical matter that those who reject the Truth may some day have their eyes opened, and then accept it, if we don't say or do something to them today that would be a memory "stumbling block" to them in the future. Don't be part of the reason for someone else choosing to throw away their salvation.
"So each of us shall give account of himself to God. Then let us no more pass judgment on one another, but rather decide never to put a stumbling block or hindrance in the way of a brother." (Romans 14:12-13 RSV)
Fact Finder: Should Christians use put-downs and insults to get their point across? See "Run 'Em Through The Muck Righteousness"