HOW SHOULD WE RESPOND TO NONBELIEVERS?

II Timothy 2:16  But shun profane and vain babblings: for they will increase unto more ungodliness. (KJV) II John 1:10-11  If there come any unto you, and bring not this doctrine, receive him not into your house, neither bid him God speed: For he that biddeth him God speed is partaker of his evil deeds. (KJV) I Peter 3:15  But sanctify the Lord God in your hearts: and be ready always to give an answer to every man that asketh you a reason of the hope that is in you with meekness and fear: (KJV)

First of all, legitimate questions from non-believers are not 'profane and vain babblings' so there is clearly no contradiction with 2 Timothy.  The 2 John passage tells us not to allow those who try to seduce us into false religions into our homes, but that doesn't mean that we should refuse to answer their questions altogether.  No contradictions here.