A friend of mine, who is a new believer, was asked a lot of questions regarding his beliefs by a few of our associate. Instead of being sincere questions, it seem to have been more of an attack on him. They asked questions such as “Were you there when the Bible was written? How do you know that the word of God is true?” I can tell that it made him feel really bad and overwhelmed because there was at least four of them. I, on the other hand, had already left the room before the conversation began but was told later about it. He asked me, “Where were you? I needed your help because they were all jumping on me.” I felt bad. However, I referred him to II Timothy where it talks about avoiding debate, such as the one I am speaking of. He had good intentions, but the other parties have an attitude of “I don’t have to go to church, but I do believe in God." Do you have any suggestions of how situations such as these should be handled in the future?
"Flee from youthful lusts; but pursue righteousness, faith, love, and peace with those who call on the Lord out of a pure heart. But refuse foolish and ignorant questionings, knowing that they generate strife. The Lord's servant must not quarrel, but be gentle towards all, able to teach, patient, in gentleness correcting those who oppose him: perhaps God may give them repentance leading to a full knowledge of the truth, in gentleness correcting those who oppose him: perhaps God may give them repentance leading to a full knowledge of the truth" (II Timothy 2:22-26).
This passage is not teach that Christians cannot debate. If such were the case, then Paul violated his own teachings. "Some men came down from Judea and taught the brothers, "Unless you are circumcised after the custom of Moses, you can't be saved." Therefore when Paul and Barnabas had no small discord and discussion with them, they appointed Paul and Barnabas, and some others of them, to go up to Jerusalem to the apostles and elders about this question" (Acts 15:1-2).
The point is that Christians are to defend their faith and answer questions when presented. "Walk in wisdom toward those who are outside, redeeming the time. Let your speech always be with grace, seasoned with salt, that you may know how you ought to answer each one" (Colossians 4:5-6). But every questioner is not seeking the truth. As you noted, some questioners are simply trying to stir up strife. Such were the type your friend ran into.
It takes experience (wisdom) to know who is being sincere and who is the trouble maker. Being a new Christian, your friend was right to ask you, as a more experienced Christian, for advice. But instead of making a blanket statement, it would have been useful to point out how to decide if a questioner is sincere or not. Also, even insincere questions can be troubling when you don't know what the answer ought to be. Use the opportunity to study the questions and the proper answers.
For example, Solomon recommends, "Answer a fool according to his folly, Lest he be wise in his own eyes" (Proverbs 26:5). So a good comeback to "Were you there when the Bible was written? So how do you know it is true?" would be: "I'll answer that one after you explain something to me, how do you know that George Washington was the first president of the United States? Where you there to see him inaugurated?" This is the method Jesus used when the Jews asked by what authority he did his miracles (Matthew 21:23-27). Even though it is too late to use this now, your friend will then be prepared if it happens again.
Another thing that will help your friend is to talk about why these people are so interested in shaking his faith. There is a reason why they can't just leave him alone and it can be eye-opening for your friend when he sees the motivation behind the questions. I usually go to Hebrews 11:7, "By faith Noah, being divinely warned of things not yet seen, moved with godly fear, prepared an ark for the saving of his household, by which he condemned the world and became heir of the righteousness which is according to faith." Now how could the personal actions of one family entering an ark condemn an entire world? It is because Noah believed God and acted upon that belief. In doing so, he proved that what God had asked was not impossible. His action destroyed any excuse the rest of the world gave. The same is true for your friend, his acceptance of Christ and his change in life proves to the rest of the people he knows that a change is not impossible. His choice is making them look and feel bad. Hence, they are trying to put things back to the way they like it -- everyone doing evil. Then, with everyone being bad, they won't feeling guilty about their own sins.
Let me recommend to things to study. First, take a look at the sermon outline called "Questions" to learn more about the different types of questions a person can encounter. Next, study Keys to Understanding, which is about how to teaching the Gospel to others. A study of "scoffers" and "mockers" would also be useful.