The rest of the question, usually in the mind of the person asking it, is, “You mean God is going to send people to Hell just because they haven’t believed in a Christ they never heard of?”

The short answer is, “No, God will not send anyone to Hell because they have never heard of Jesus.”  Notice I did not say, “People will not go to Hell.”  But the truth is that no one will go to Hell because they have not heard of Jesus.  Hell is not the penalty for ignorance, it is the penalty for sin.  God will not send anyone to Hell for their ignorance. It is sin that by its very nature condemns us and sentences to an eternal separation from God in hell. But that need not be the end.

The Bible says that no one is ignorant when it comes to God.  (Romans 1:19-21)

There are several ways God reveals Himself in this world.

a. The light of Creation
(Rom 1:20 & Ps 19:1-3)
Every person of every language and dialect has “heard” the voice of God through what He has made. It is the light of creation that shines on every heart and opens every mind that does not shut Him out.

b. The light of Conscience
In Romans 2, God’s Word says that every person’s conscience will either accuse or excuse him on the day when God will judge the secrets of their hearts. God has placed in everyone the knowledge of right and wrong, He has given us a moral compass. We can choose to sear the conscience through immoral and ungodly behavior, but we’re still responsible. No one is able to completely turn off his or her moral conscience. There is always something there that tells us what is right and what is wrong, even if we try to convince ourselves that the thing we are doing is OK.

No one can hide behind the claim of ignorance. No one can say because they have never been given the Ten Commandments they aren’t guilty. The law is written on every heart. (Rom 2:1,3)

God uses the light of Creation and light of Conscience to get the attention of every person on the face of the earth. We are judged according to the way we respond to the light we have been given, not on the basis of something we have never heard. People are not condemned for what they don’t know or haven’t done, but for what they DO know and for what they HAVE done. And God is perfectly just and therefore, will judge each one perfectly.

c. The light of Christ
Not everyone in the world has this light. The only way to receive grace and mercy instead of simply justice is to receive the light of Christ. This is where we as Christians come in. It’s our responsibility to share the light of Christ with others. We need to share the Gospel with those who have never heard or who have never really listened. 

Romans 1- All have seen the light of Creation and are without excuse. 
Romans 2- All have heard the light of Conscience and are without excuse. 
Romans 3- It’s our responsibility to take the light of Christ to those who have no excuse.

When you feel a person is bringing up the “heathen in Africa” argument simply as a smoke-screen and diversion, you might respond something like this:  “If you’re truly concerned about the person in Africa who hasn’t heard, why don’t you just come to Christ and then go tell them about Him yourself?” That should be enough to clear the smoke away.

NO one will ever be condemned for not believing in a Christ he never knew. He will be condemned for rejecting the God he did know and for worshipping the idols he set up in God’s place; And he will be condemned for what he has done when his conscience told him not to do it. People will be condemned for their ingratitude for the light and for the gifts God has given to them and for the sins they have committed when they knew they were wrong. It is "sin" that condemns… that is why we need a Savior.

Ask anyone, anywhere in the world if they have ever done something they believed to be wrong. Know what they will say? “Ha, ha, ha, of course, everybody has.” We all know we have done things wrong. If all men condemn themselves, why should they be surprised if God also condemns them?