There are times in relationships where we must call people to accountability for their actions or attitudes. We see they are headed for trouble or are already deep in sin, and following the command of Scripture we prayerfully set out to confront them. 
We begin with a biblical reproof. We are commanded to reprove one another for the sake of becoming more like Christ. 
…be subject to one another in the fear of Christ. Ephesians 5:21b (NASB)
We are to tell a fellow Christian (husband, child, friend, anyone!) when they are sinning.  Of course, there are some important guidelines involved that must be followed or disaster might ensue! 
First, the motive must be restorative. Motive is what determines if this action is reproof or revenge. If your desire is to make them suffer or pay for their sin and resulting harm to you or others then you had best set your part in this action aside for now.  If you attempt to reprove someone when your heart is focused on yourself, your motives will not be right and you will do more harm than good.  This is why Galatians 6:1 is so important when rebuking a sinning brother or sister in Christ. 
Brethren, even if anyone is caught in any trespass, you who are spiritual, restore such a one in a spirit of gentleness; each one looking to yourself, so that you too will not be tempted. Galatians 6:1 (NASB)
Your rebuke must be done gently and humbly. You must first look within your own heart and through prayer and meditations ask the Lord to reveal your own areas of sinfulness before you approach another person about theirs. 
Why do you look at the speck that is in your brother’s eye, but do not notice the log that is in your own eye? “Or how can you say to your brother, ‘Let me take the speck out of your eye,’ and behold, the log is in your own eye? “You hypocrite, first take the log out of your own eye, and then you will see clearly to take the speck out of your brother’s eye. Matthew 7:3-5 (NASB) 
Too often, a person desiring to reprove another has not taken the necessary steps of confession and repentance for their own sin. This is revealed in their attitude of superiority as they reprove you. This is not loving nor is it kind. It is a grand hypocrite who is unwilling to clear up their own spiritual matters before confronting a fellow sinner. 
For your reproof to be biblical and not vengeful you cannot be angry or bitter toward the person you are reproving. Remember that the goal is to urge them on toward Christ-likeness and “anger does not bring about the righteous life that God desires” (James 1:20) for you or the one you are reproving.