APOLOGETICS - NOT AN OPTION
God Intended it:
The Bible clearly teaches that man was created in the image of God and even with the fall, that imageness, though greatly marred, defines our humanity. With nature and man being created by Him, it is logical to assume a divinely intended correspondence between the material world and the mind of man. While salvation is found in Jesus Christ alone, God has revealed himself in such a way as to make himself absolutely and universally known to all people.
Christians Need It:
As a bi-vocational minister for over 30 years, I have seen the "trickle down" effect mentioned by Francis Schaeffer first hand. Skepticism and other non-biblical philosophies are no longer confined to the university campus because they now exist, universally, in the workplace. It is there that the war on truth emerges and every believer must be prepared for battle in order to present Christ to a lost world.
The Bible Assumes and Commands It:
1 Peter 3:15
"But sanctify the Lord God in your hearts: and be ready always to give an answer (apologia = apologetics) to every man that asketh you a reason of the hope that is in you with meekness and fear."
2 Corinthians 10:5
"Casting down imaginations and every high thing that exalteth itself against the knowledge of God, and bringing into captivity every thought to the obedience of Christ..."