This is the third step in salvation.

Once you accept Christ as your savior by believing in him, according to your faith in him

you are justified. This happens at the moment of your accepting Christ. Once you have

been justified this puts you in the right standing with God,  a permanent position.
 

Justification- simply means being declared righteous; a legal term…..
 

God pronounces you righteous in spite of your sins. This is the righteousness of God and can only come from God.
 

Apart from Gods righteousness we are left with our own righteousness, which is as filthy rages. (Although some people believe that their righteousness is good- this is what’s considered  as being self-righteous)
 

Even though we have been justified, it doesn’t mean that we haven’t sinned or won’t sin

but that in the eyes of the Lord we are justified apart from our sins. (Not that we haven’t sinned but as if we haven’t sinned)
 

Just as sin is imputed (ascribed) to all man, so also is the righteousness of God imputed

unto us. (Rom. 5:19)
Justification only comes by Faith. (Rom.3:22-28)
 

Romans 5:16-17
16 And not as it was by one that sinned, so is the gift: for the judgment was by one to condemnation, but the free gift is of many offense unto justification. 17 For if by one man's offense death reigned by one; much more they which receive abundance of grace and of the gift of righteousness shall reign in life by one, Jesus Christ.)