According to Wikipedia, justification is God's righteous act of removing the guilt and penalty of sin. Romans 4:25 in the Easy to Read version says, Jesus was handed over to die for our sins, and he was raised from death to make us right with God. It's like you committed a crime and went to court but someone else pleaded guilty and went to prison in your place. Justification is being found not guilty by God because Jesus did the time for your crime.
Romans 5:18 (NIV)
Just as one trespass resulted in condemnation for all people, so also one righteous act resulted in justification and life for all people.
It's a bit easier to understand in the Easy Read Version.
Romans 5:18 (ERV)
One sin of Adam brought the punishment of death to all people. But in the same way, Christ did something so good that it makes all people right with God. And that brings them true life.
Sin entered the world when Adam and Eve disobeyed God. And it was defeated when Jesus died and rose again. That's justification.
CHALLENGE: Spend some time reflecting on how awesome it is that you are free and forgiven when you deserved to be penalised and punished.
Short and sweet inspirations for Christian teen girls.