Here is another long citation from Bernard Ramm on the benefit and purpose of Christian evidences and apologetics. 
“At this point the purposes of Christian evidences for the Christian should be made evident: 
- The      Christian is established in his faith not only experientially, but      intellectually and factually. He sees the Christian religion not only as that      which gives him a blessed experience of salvation and assurance within his      heart, but also as s system universal and factual in its scope. He sees it      in its cosmic, historic and factual breadth. His personal experience is      thus related to a universal and valid system of religion. The snipings of      psychologists at his religious conversion are emptied of much of their      pertinence, for although his religious convictions commenced with his      conversion, they now no longer rest solely on such a narrow base, but are      part of a comprehensive world view.
 
- Further,      the Christian well versed in Christian evidences understands the nature of      many of the attacks on the Christian faith, and knows their invalidity.      His knowledge of textual criticism enables him to silence the argument      that the text of the Bible has been appreciably tampered with during the      course of its transmission; his knowledge of literary criticism enables      him to defend the trustworthiness of his documents; his knowledge of all      the other items in the arsenal of Christian evidences is a powerful weapon      for not only the silencing of attacks on the faith, but the positive evangelistic      presentation of the Gospel of Christ.
 
- Apologetic      and Christian evidences are not the gospel, but if a person has a      prejudice against the gospel it is the function of apologetics and      evidences to remove that prejudice. The value of apologetics and evidences      for evangelistic purposes (public, personal conversation, literature) is      too frequently underrated usually on the grounds that people are won by      preaching of the Word alone. 
 
Two observations are pertinent to this assertion:
- First,      no well-grounded apologist will state that the philosophic demonstration      of Christianity saves a man, but it is, to the contrary, quite evident      that no man will give the necessary credence to the Word if he has certain      notions and biased opinions about the facts and nature of the Christian      religion. Apologetics and Christian evidences cut down these objections to      enable the gospel once again to directly confront the consciousness of a      person. Spurgeon’s oft-quoted remark that the Bible is a lion that defends      itself is very pious of sound, but very fallacious of fact. The huge      slashes of radical criticism into the Christian church reveal the Bible is      defenseless unless defended by its believers. Is every cavil, every      slander, every false accusation, every gross misrepresentation to go      unnoticed, unanswered, unchallenged? Can the stabs at the vitals of      theology be answered by quoting a verse or two of Scripture? We think not.      Christian evidences and Christian apologetics are indispensible to the      health, welfare and progress of the gospel.
 
- Second,      the opponents of Christianity figure that it is worthwhile to argue their      case. It is the basic theory of all propaganda that successful efforts are      possible by argumentation, specious or genuine. Lunn correctly observes      that ‘Nobody is ever converted by argument’ is a formula as popular with      Christians as it is unknown among politicians and political canvassers…Human      opinion is not always formed from argumentation, but a good measure of it      is, and therefore Christian evidences is the Christian arsenal of data and      facts for any Christian who wishes to defend and debate his faith.”
 
                                                                           Bernard Ramm, “Protestant Christian Evidences,” pp 14-16 
