First off the field of Apologetics is not an apology. Apologetics is derived from the New Testament greek word apologia (a-polla-gee-ya). It means to defend or make a defense for, like in a courtroom.
The Christian faith has been attacked and perverted since its beginnings in the 1st Century A.D. Paul had to defend the gospel against Gnostic beliefs as well as the intermingling of Jewish tradition. The book of Galatians would not have had to be written if it weren't for falsehoods and ideas contrary to the gospel!
The defense of the Christian faith is thoroughly biblical. Paul was inspired to write several scriptures dealing with false teachers and false prophets who were ultimately attempting to pervert the gospel message.
The noun apologia is used eight times in the New Testament.
The verb apologeomai is used ten times in the New Testament.
Also, Jude 1:3 urges us to contend for the faith. We have to know why we believe what we believe. This is even more important in the 21st Century where the average "thinker" concludes that what is true for you is true for you and what is true for me is true for me... If we are sincere in our beliefs then we are fine. Guess what? That couldn't be further from the truth.
That is why the Bereans in Acts 17:11 were cited as being more noble than the Thessalonicans, because they labored in the word daily, making sure that what the Apostles said was so. Following their example the Body of Christ needs to have a personal understanding of what the Christian faith teaches and then be able to coherently defend what it teaches. So no matter if you are a babe in Christ or have been a Christian for quite some time, you are called to defend the truth of Christianity on some level.
Please check out the following links to learn more about the field of apologetics:
CARM's apologetics page
Regarding Apologetics, An Apology
Apologetics and Evangelism
