This comes from question 60 of the Heidelberg Catechism. Gold.
Q. How are you right with God?
A. Only by true faith in Jesus Christ.
Even though my conscience accuses me of having grievously
sinned against all God's commandments
and of never having kept any of them,
and even though I am still inclined toward all evil,
without my deserving it at all,
out of sheer grace,
God grants and credits to me
the perfect satisfaction, righteousness, and holiness of Christ,
as if I had never sinned nor been a sinner,
as if I had been as perfectly obedient
as Christ was obedient for me.
All I need to do
is to accept this gift of God with a believing heart.
Praise God! This is the best news ever! What a gracious father! Without deserving it at all, God, out of sheer grace, grants and credits to Christians the perfect satisfaction, righteousness, and holiness of Christ. Understanding this truth is imperative to understanding the Gospel, and I pray God continues to enliven my heart to the glorious riches of Christ's saving work.