"Righteousness exalts a nation, but sin is a reproach to any people." (Proverbs 14:34)

Sin is always shameful. Some of the sins people commit might not be that shameful in front of men, but they're always shameful in the eyes of God.

Sin is more than just shameful. When a Christian commits sin, not only does he teach unbelievers that sin is OK in the eyes of God; it also tells unbelievers that both Christians and non-Christians alike sin -- and so why be a Christian?

While we Christians must never condemn ourselves for how people respond to us and everything we say or do, we must be very mindful and cautious about how we live in front of people. This is because we have a testimony to protect, the same testimony we use to witness about the Lord Jesus Christ.

So, what should we Christians do when we commit sin and it's been seen by unbelievers?

In plain sight

The Bible tells us that we should be careful in living our lives in front of men. Being careful to live right in the sight of God includes living right in the sight of men.

While we don't live to please men, we live right in front of them in order to please God and give a Godly testimony to people:

"Fight the good fight of faith, lay hold on eternal life, to which you were also called and have confessed the good confession in the presence of many witnesses." (1 Timothy 6:12)

"Therefore we also, since we are surrounded by so great a cloud of witnesses, let us lay aside every weight, and the sin which so easily ensnares us, and let us run with endurance the race that is set before us..." (Hebrews 12:1)

"Repay no one evil for evil. Have regard for good things in the sight of all men. If it is possible, as much as depends on you, live peaceably with all men." (Romans 12:17-18)

While these passages don't mean we should please people, all of these tell us that our witness, our testimony is important and we must take care of it.

When we've done something that can harm that testimony we need to take remedial steps.  

Here are three things we need to do.

1) Repent of our sin

Repentance is always a good thing. If ever we commit sin, we must never try to justify or explain it away. We must simply repent.

2) Apologize to those who were offended

Since the sin was committed in front of people, chances are some of them could be offended, or otherwise affected.

When we do this to the people who were watching us as we commit sin, we show them that God doesn't want Christians to live in sin.

3) Make restitution where necessary

Lastly, if sin is committed in front of the unbelievers, Christians must be quick to apologize and make restitution if necessary.

Repentance is often followed by actions showing an eager desire to live right before the Lord. These actions are called "restitution." Luke 19:8 gives us one great example through Zacchaeus:

"Then Zacchaeus stood and said to the Lord, "Look, Lord, I give half of my goods to the poor; and if I have taken anything from anyone by false accusation, I restore fourfold.""