One hears stories of doubtful Christians who when they seek counsel from their pastor or parents they are told to suppress their doubts and just believe.

Veritas Splendor

The truth of the matter matters. The Bible exhorts us to thirst for, seek, analyze, and defend the truth. The Apostle Paul spends much of his letters dispelling falsehoods and warning against false teachers.

Knowledge and Insight | Philippians 1:9-11

And this is my prayer: that your love may abound more and more in knowledge and depth of insight, 10 so that you may be able to discern what is best and may be pure and blameless until the day of Christ, 11filled with the fruit of righteousness that comes through Jesus Christ — to the glory and praise of God.

Education | Acts 7:21-6

22 Moses was educated in all the wisdom of the Egyptians and was powerful in speech and action.

Skepticism and Testing Claims

Testing Against the Scriptures | Acts 17

11 Now the Berean Jews were of more noble character than those in Thessalonica, for they received the message with great eagerness and examined the Scriptures every day to see if what Paul said was true.

Test All, Hold on to the Good | 1 Thessalonians 5

20Do not treat prophecies with contempt 21but test them all; hold on to what is good, 22reject every kind of evil.

Rationality

Reasoning at Length with Others | Acts 17

2As was his custom, Paul went into the synagogue, and on three Sabbath days he reasoned with them from the Scriptures, 3explaining and proving that the Messiah had to suffer and rise from the dead. “This Jesus I am proclaiming to you is the Messiah,” he said. 4Some of the Jews were persuaded and joined Paul and Silas, as did a large number of God-fearing Greeks and quite a few prominent women.

16 While Paul was waiting for them in Athens, he was greatly distressed to see that the city was full of idols. 17 So he reasoned in the synagogue with both Jews and God-fearing Greeks, as well as in the marketplace day by day with those who happened to be there. 18 A group of Epicurean and Stoic philosophers began to debate with him.

Arguing Persuasively | Acts 19:8-10

8 Paul entered the synagogue and spoke boldly there for three months, arguing persuasively about the kingdom of God. 9 But some of them became obstinate; they refused to believe and publicly maligned the Way. So Paul left them. He took the disciples with him and had discussions daily in the lecture hall of Tyrannus. 10 This went on for two years, so that all the Jews and Greeks who lived in the province of Asia heard the word of the Lord.

Empirical Evidence

Eyewitnesses | 2 Peter 1:16-19

For we did not follow cleverly devised stories when we told you about the coming of our Lord Jesus Christ in power, but we were eyewitnesses of his majesty. 17 He received honor and glory from God the Father when the voice came to him from the Majestic Glory, saying, “This is my Son, whom I love; with him I am well pleased.”[a] 18 We ourselves heard this voice that came from heaven when we were with him on the sacred mountain. 19 We also have the prophetic message as something completely reliable, and you will do well to pay attention to it, as to a light shining in a dark place, until the day dawns and the morning star rises in your hearts.

Convincing Proofs | Acts 1:3

After his suffering, he presented himself to them and gave many convincing proofs that he was alive. He appeared to them over a period of forty days and spoke about the kingdom of God.

Careful Investigation and Record | Luke 1

1 Many have undertaken to draw up an account of the things that have been fulfilled among us, ²just as they were handed down to us by those who from the first were eyewitnesses and servants of the word. 3 With this in mind, since I myself have carefully investigated everything from the beginning, I too decided to write an orderly account for you, most excellent Theophilus, 4 so that you may know the certainty of the things you have been taught.

Earthly Things as Credibility about Heavenly Things | John 3:11-12

11 Very truly I tell you, we speak of what we know, and we testify to what we have seen, but still you people do not accept our testimony. 12 I have spoken to you of earthly things and you do not believe; how then will you believe if I speak of heavenly things?

Testimony

Trusting the Testimony of the Authors | John 20

29Then Jesus told him, “Because you have seen me, you have believed; blessed are those who have not seen and yet have believed.” 30 Jesus performed many other signs in the presence of his disciples, which are not recorded in this book. 31 But these are written that you may believe that Jesus is the Messiah, the Son of God, and that by believing you may have life in his name.

Contend for Truth

Once the truth has been thought to be found, it’s worth fighting for.

False Prophets will Come | Matthew 24:24-25

False messiahs and false prophets will come and do great miracles and wonders, trying to fool the people God has chosen, if that is possible. Now I have warned you about this before it happens.

Beware a Different Gospel | Galatians 1:8-9

But even if we or an angel from heaven should proclaim to you a gospel contrary to what we proclaimed to you, let that person be condemned! What we have told you in the past I am now telling you again: If anyone proclaims to you a gospel contrary to what you received, let that person be condemned!

Contend for the Gospel | Jude 1:3

Dear friends, although I was very eager to write to you about the salvation we share, I felt compelled to write and urge you to contend for the faith that was once for all entrusted to God’s holy people.

2 Corinthians 11:4-6

For if someone comes to you and preaches a Jesus other than the Jesus we preached, or if you receive a different spirit from the Spirit you received, or a different gospel from the one you accepted, you put up with it easily enough. I do not think I am in the least inferior to those “super-apostles.” I may indeed be untrained as a speaker, but I do have knowledge. We have made this perfectly clear to you in every way.

Demolishing Arguments | 2 Corinthians 10:3-5

For though we live in the world, we do not wage war as the world does. 4 The weapons we fight with are not the weapons of the world. On the contrary, they have divine power to demolish strongholds. 5 We demolish arguments and every pretension that sets itself up against the knowledge of God, and we take captive every thought to make it obedient to Christ.

Correct and Rebuke with Careful Instruction | 2 Timothy 4:2-4

2Preach the word; be prepared in season and out of season; correct, rebuke and encourage—with great patience and careful instruction. 3For the time will come when people will not put up with sound doctrine. Instead, to suit their own desires, they will gather around them a great number of teachers to say what their itching ears want to hear. 4They will turn their ears away from the truth and turn aside to myths.

Miracles, Mark chapter 2

Polemics and Rhetoric Ethics

1 Peter 3:8-16 | Reason, Gentleness, Respect

Notice the strong call to goodness, sympathy, love, and respect as the context in which giving reason happens. Also notice the presumption of honesty and a clear conscience. This is no exhortation to slick salesmanship.

Finally, all of you, live in harmony with one another; be sympathetic, love as brothers, be compassionate and humble. 9 Do not repay evil with evil or insult with insult, but with blessing, because to this you were called so that you may inherit a blessing. 10 For, “Whoever would love life and see good days must keep his tongue from evil and his lips from deceitful speech. ¹¹ He must turn from evil and do good; he must seek peace and pursue it. ¹² For the eyes of the Lord are on the righteous and his ears are attentive to their prayer, but the face of the Lord is against those who do evil.” ¹³ Who is going to harm you if you are eager to do good? ¹⁴ But even if you should suffer for what is right, you are blessed. “Do not fear what they fear; do not be frightened.” ¹⁵ But in your hearts set apart Christ as Lord. Always be prepared to give an answer to everyone who asks you to give the reason for the hope that you have. But do this with gentleness and respect, 16 keeping a clear conscience, so that those who speak maliciously against your good behavior in Christ may be ashamed of their slander.

Apologetics 101: The Biblical Warrant for Apologetics

http://www.radicaltruth.net/index.php?option=com_content&view=article&id=54:apologetics-and-polemics&catid=11:radical-truth-christianity&Itemid=9