Below is a good read from Douglas Groothuis regarding arguments to avoid when defending your Christian Faith:
Apologetics is a necessary discipline for the Christian faith. Jesus and the Apostle Paul regularly defended their beliefs through rational arguments. The Apostle Peter tells us to be ready to give a reason for the hope we have in Christ (1 Peter 3:15). This lost world needs to hear and believe the gospel of God. So, when unbelievers ask questions about the truth and rationality of Christianity, we must be ready with sufficient answers, trusting in the Holy Spirit to apply the message to their souls (Acts 1:8).
However, some apologetic arguments—no matter how sincerely or repeatedly stated—are nonstarters. They fall flat and do not serve the cause of Christ simply because they are bad arguments. Four of these arguments are so common and so detrimental to the cause of rational Christian witness that they need to be addressed. As T. S. Eliot wrote in his play Murder in the Cathedral:
The last temptation is the greatest treason;
To do the right deed for the wrong reason.
To do the right deed for the wrong reason.
Defending Christianity as true, rational, and pertinent is right; to do so for the wrong reasons is wrong.
Nonstarter #1: Since we do not know everything, no one can disprove the existence of God. God might be somewhere outside of our knowledge. Moreover, if we knew everything—which is the only way to disprove God—we would end up being God ourselves and, thus, atheism would be false!
Although starting from a legitimate insight, this argument extends its claim too far. Proving a universal negative is more arduous than substantiating a universal affirmative. A man once insisted to me that the Bible contained the sentence, “God helps those who help themselves.” (Sadly, many Christians believe this as well.) I denied this and informed him that I had read the Bible many times, but never read those words. He replied, “It must be in there somewhere.” Proving that the Bible does not contain this statement was considerably more difficult than proving that the Bible does contain the statement: “God so loved the world that he sent his one and only Son” (John 3:16). (This encounter occurred before computer searches made things simpler.)
However, the existence of God is not like the placement of a statement in the Bible. God is not a finite, empirical object that can be perceived in the way that a sentence is perceived. God is not directly visible under normal conditions. (Theophanies—or divine appearances—occur in Scripture, but are unpredictable. However, at death, we will all see God.). Arguing for or against God’s existence is, therefore, a more involved and multidimensional endeavor. Simply appealing to people’s ignorance as finite beings in no way by itselfshows that unbelief in God is not justified. Moreover, one need not know everything to deny the existence of some objects. The belief that there are no unicorns is rationally compelling, even though I cannot rule out the possibility that a flesh-and-blood unicorn may be hiding somewhere. The odds are tremendously against unicorns being anything other than a fantasy animal. So one does not have to know everything even with respect to perceptible objects in order to rule out the existence of some types of entities. The same argument applies to centaurs, fairies, pro-life Democratic candidates for high elected office. Nevertheless, the astute apologist should argue that if the unbeliever has not sufficiently investigated the case for the existence of God, then she is not in a good position to deny God’s existence or even to remain skeptical.
Just as the person who has heard only a few pieces of jazz music is not qualified to make an aesthetic judgment on jazz, so the philosophical neophyte is in no position to make an informed and wise judgment about God’s existence. Serious intellectual work needs to be done, especially given the potential benefits and losses relative to one’s relationship to the God of Christian theism: “Whoever has the Son has life; whoever does not have the Son of God does not have life” (1 John 5:12).
Nonstarter #2 People do not die for a lie. But the apostles died for their belief in the resurrection of Jesus, so they must have died for the truth.
On the contrary, people do die for lies all the time in our fallen world. The Muslim hijackers of September 11, 2001, died for the belief that they would be rewarded for their savagery with attending virgins in paradise. Hitler committed suicide in his bunker still believing in Nazism.
The problem with nonstarter #2 is that it is nearly true, but it misses the truth nevertheless. The truth is something like the following: People do not die forwhat they know to be a lie, unless they can find some tremendous advantage in so doing. Therefore, it makes no sense to think that Jesus’ first disciples went to their deaths for their belief in Jesus as the resurrected Messiah, if they in fact knew he was moldering in a tomb. One might argue that they created the idea of the resurrection out of whole cloth in order to benefit themselves in some way, but this does not hold water. There is no evidence that they would have bettered themselves in any earthly way by this tactic. Nor is there any reason to think that they should believe themselves to be in that advantageous position even if they were not. Preaching a dead messianic pretender as the Lord of Life had no sales potential whatsoever. Even if these benighted religious opportunists thought that the scheme might work, they would have surely recanted in the face of the sword. But there is no evidence that they did. As Pascal so wisely put it:
The hypothesis that the Apostles were knaves is quite absurd. Follow it out to the end and imagine these twelve men meeting after Jesus’ death and conspiring to say that he had risen from the dead. This means attacking all the powers that be. The human heart is singularly susceptible to fickleness, to change, to promises, to bribery. One of them had only to deny this story under these inducements, or still more because of possible imprisonment, tortures and death, and they would all have been lost.
Nonstarter #3: Evolution (meaning Darwinism) cannot be proven because it is not scientific. Science demands repeatable and empirical observation: things that can be observed through a microscope or a telescope or chemical reactions in a test tube. Therefore, evolution is unscientific and has no final claim on reality.
The true insight in this argument is that Darwinism is based on forensic considerations about the distant past. One cannot observe speciation or life coming from non-life (abiogenesis) as part of experimental science. Yet scientific enterprise encompasses far more than repeatable or directly observable matters. It considers singularities such as the origin of the universe, the origin of life, and the origin of species, among others. Science addresses both present day operations, such as virus mutations, and events in the remote past, such as geological formations, animal and human migrations, and so on. These are all properly part of science.
This “it isn’t really science” approach to origins can only yield intellectual parity (or a kind of stand-off) with the Darwinian account. The claim is that neither option is really scientific nor can either be proved; but one can have faith in either. If so, Darwinism and a biblical view of creation are on an even footing. But there is considerable empirical evidence at both the macroscopic and the microscopic levels for intelligent design in nature. Present day observations of the bacterial flagellum along with the principles of design detection warrant the inference that it was designed in the distant past, even though we cannot observe any such designing activity in the present. We may not see the cause of the design, but we can discern the effects of design through scientific observation and reasoning.
Nonstarter #4: You cannot argue with a changed life. A Christian’s testimony is the most powerful and irrefutable apologetic. (Some say it is the only apologetic needed.)
The germ of truth here is that Jesus Christ does radically change people for the better. We are “new creations” in Christ (2 Corinthians 5:17). If there were no evidence of moral and spiritual change (and continued faith and growth) in Christians, Christianity would be refuted, since it predicts such things. Francis Schaeffer earnestly argued that Christians, as the bride of Christ, must bear fruit through their status as God’s justified and sanctified children.Moreover, Christianity has been, on balance, a far better force for good than for evil in history. Christians outlawed the slave trade, promoted education and hospitals, gave women the vote, and more.
Nevertheless, there is much more to apologetics than telling one’s testimony, no matter how dramatic. Even if God has brought powerful changes for the better in our lives, the unbeliever may still question the source of the change. The effect is real, but what is the cause? Some wonder if belief may act as a placebo. Even though the new birth is available only by the reception of the Gospel through the Holy Spirit (John 3), positive life changes occur for many non-Christians as a result of new beliefs or behaviors. They, too, have testimonies. Mormons are noteworthy in this respect.
But where Christians differ from Mormons and others is that they have a whole toolbox of apologetic arguments at their disposal. A strong testimony and a godly life since conversion must be supplemented with the ability to give honest answers to the unbeliever’s honest questions about the existence of God, the problem of evil, the reliability of the Bible, the claims of other religions, and so forth.
In order for a Christian to defend the faith given once for all to the saints (Jude 3), he must never commend this glorious gospel with shabby or hollow arguments. God has something far greater in mind for us: believing the right thing for the right reason.God Bless,
 T. S. Eliot, Murder in the Cathedral (New York: Harcourt, 1964), (44).
 See William Lane Craig, Reasonable Faith (Wheaton, IL: Crossway, 1994) and J.P. Moreland, Scaling the Secular City (Grand Rapids, MI: Baker, 1987).
 Blaise Pascal, Pensées, ed. Alban Krailsheimer (New York: Penguin, 1966), (310/801).
 See Norman Geisler and Kerby Anderson, Origin Science (Grand Rapids, MI: Baker Books, 1987).
 See William Dembski, The Design Revolution (Downers Grove, IL: InterVarsity Press, 2004).
 Francis Schaeffer, True Spirituality, 30th anniversary ed. (Wheaton, IL: Tyndale, 2001).
 See Alvin Schmidt, How Christianity Changed the World (Grand Rapids, MI: Zondervan, 2004).