The sad part is that many Christians forget this and sometimes look down on others for their sins. In God's eyes, it does not matter whether you have committed adultery or just told a lie -- they are all the same to Him. Sin is sin.
I recall a true story about a young woman who visited church one day and sat in the very back. Various members took note of her presence and began to whisper numerous comments about her -- some even sneering at her. Seems she was a former prostitute. Here she was trying to straighten out her life and worship God, and all they could think was, "How dare she show up in church."
Why can't we look past people's cirumstances to see the person inside. Is there not one of us that sins. Jesus encountered a similar situation when some Pharisees brought before him a woman caught in the act of adultery. He wisely confronted them with their own sin by saying, "If any one of you is without sin, let him be the first to throw a stone at her."
We must have compassion on others, no matter what their sin is -- for in truth, we are really no better. Not one of us can by our own righteousness even enter the kingdom of heaven. It is only because Jesus shed his blood to atone for our sins that we have a means by which to be forgiven. Therefore, we should lift each other up, admonishing each's sin in the Lord's name, but still serving God's love and forgiveness.