When you are debating with a non-Christian, the Bible is not your common authority so you must use another ways of proving something.
Logic and science/common knowledge are probably two most important in such a case. I also find philosphy (in the original meaning of the word) to be very useful too.
The use of the Bible is for them to understand why you believe in Him as your personal testimony is how you apply your faith & hope in Jesus Christ and what He has done for you so that others may hope in Him to believe in him too.
When conversion is not done by the persuasion of a man's speech, but by the Spirit's power, then even stutterers can witness depending on Him to provide the seed for the sower and water for the water of what is needed for God to cause the increase by.
But yes, when "debating" with non-Christians, the Lord may lead you to other knowledge for them to reconsider their beliefs to lean towards your belief by the scripture & your personal testimony of your hope in Christ for what He has done for you & not just having given you eternal life. They may look at their sinful state in how they are getting worse & worse and place their hope in Him to call on Him to be saved from their self destructive sins as well as receive eternal life by God's grace.
Every situation is different, but we can trust the Lord in being our Good Shepherd to know when to share or not to share and even when to debate or not to debate.
Psalm 37:[SUP]5 [/SUP]Commit thy way unto the Lord; trust also in him; and he shall bring it to pass.[SUP]6 [/SUP]And he shall bring forth thy righteousness as the light, and thy judgment as the noonday.
Matthew 7:[SUP]6 [/SUP]Give not that which is holy unto the dogs, neither cast ye your pearls before swine, lest they trample them under their feet, and turn again and rend you.[SUP] 7 [/SUP]Ask, and it shall be given you; seek, and ye shall find; knock, and it shall be opened unto you:[SUP]8 [/SUP]For every one that asketh receiveth; and he that seeketh findeth; and to him that knocketh it shall be opened.
Acts 16:[SUP]6 [/SUP]Now when they had gone throughout Phrygia and the region of Galatia, and were forbidden of the Holy Ghost to preach the word in Asia,[SUP]7 [/SUP]After they were come to Mysia, they assayed to go into Bithynia: but the Spirit suffered them not.
[SUP]8 [/SUP]And they passing by Mysia came down to Troas. 9And a vision appeared to Paul in the night; There stood a man of Macedonia, and prayed him, saying, Come over into Macedonia, and help us. 10And after he had seen the vision, immediately we endeavoured to go into Macedonia, assuredly gathering that the Lord had called us for to preach the gospel unto them.
It is very possible with all the false teaching that are out there on how any one is saved, they may not have heard the real gospel of Jesus Christ in why He is the Good News to man.
A lady I had used to work with had thought she had to clean up her life first before coming to Jesus. I do not know what turned her away into thinking like that, but I can imagine the altar call to make a commitment to follow Christ can be an example to cause sinners to walk away from Him when they do not see it in themselves to make such a commitment when they are being honest about how sinful they are for they do the things that they would not... and not do the things that they should.
I had told her that THAT was what Jesus Christ came to do.. not just give us eternal life but to save us from our sins, and that she could come to Him now to be saved by Him and He will help her to follow Him.
But when it comes to debate... yeah... if they are open to the discussion in not being a mocker about it, but even then, trust the Lord to lead you as to when to share & when not to share, because not every debater is even interested in seeking the truth if they are only interested in taking away your faith in Him or somehow make you look ignorant about some knowledge outside of the Bible that he thinks is true as the world does, but not in according to the word of God.
We walk by faith... and so that is how we should minister too. And if we make mistakes and find ourselves in a heated debate, one can rely on Jesus Christ as our Good Shepherd to provide the escape to walk away before it gets violent while praying to the Father to forgive them for they know not what they do, even when if by some chance, they are killing us.