There is a branch of theology that has to do with the defense and proofs of Christianity. It is known as “apologetics.” It has nothing to do with saying you’re sorry for something. “Apologetics” comes from the Greek word apologia, meaning “defense” or “answer.” (So the Apology to the Augsburg Confession is a defense of that document). This word, apologia, occurs several times in the Greek New Testament. One passage is 1 Peter 3:15-16:
“Always be prepared to give an answer (apologia) to everyone who asks you to give a reason for the hope that is in you. But speak with gentleness and respect, while maintaining a clear conscience, so that those who attack your good way of life in Christ may be put to shame because they slandered you as evildoers” (1 Peter 3:15-16 EHV).
So “apologetics” has nothing to do with apologizing, as though we should be embarrassed by the gospel. Nor is apologetics a clever method of converting unbelievers with all sorts of arguments from logic, science or philosophy. Faith is created by the Holy Spirit alone through the gospel in word and sacraments (the means of grace or tools of the Holy Spirit). Apologetics does not attempt to explain what cannot be explained (the mystery of the Trinity, the two natures in Christ, the doctrine of election, etc.).
True Christian apologetics is to “give an answer” on the basis of what God has said in the Holy Scriptures. Even among those who do not accept the Bible as God’s word, the gospel is the power of God for salvation. God’s word carries its own power to convince and convert. It is helpful to know where others are coming from. An atheist has different notions than a Jehovah’s Witness. It is possible to expose weaknesses in the foundations on which unbelievers are building their lives, to point out that many arguments against the gospel are not as convincing as they seem. But we dare not make the mistake of thinking that the “scientific” observations of a Christian are sure and certain because one is a Christian. Science is a constantly changing explanation of what we see around us. If we build our faith on “scientific” arguments or even “logical” arguments in instead of on the gospel, then what happens to that faith when a better argument comes along? Our weapon is “the sword of the Spirit, which is the word of God” (Ephesians 6:17 EHV). It is the sword Jesus used. It is our sword too.