"For I am not ashamed of the gospel of Christ: for it is the power of God unto salvation to everyone that believeth; to the Jew first, and also to the Greek. For therein is the righteousness of God revealed from faith to faith: as it is written, The just shall live by faith." Romans 1:16-17
From faith to faith. This verse has been grossly misunderstood over the years. It doesn't mean that the righteousness of God is revealed to those of different faiths or transferred from one faith (Christianity) to another faith (Islam). It also doesn't mean that the gospel is present in differing faiths; That somehow if you acknowledge some story about Jesus, you have received the gospel.
What the verse is speaking to is your internal faith growth. As you learn to live by faith your faith is increased, thus faith to faith. To the Jew, the Gentile, the Muslim, the Hindu, the Shintoist, to everyone seeking God, the message is: receive the gospel of Jesus Christ for in it is the power of God. The gospel contains the power of God, no other message, no other faith.
"There is one body, and one Spirit, even as ye are called in one hope of your calling; One Lord, one faith, one baptism," Ephesians 4:4-5
Now that we have settled that, is your faith growing? Have you been meeting with Jesus and unlearning the things that cultural Christianity has taught you? Have you been exercising your faith and moving forward truth upon truth learning truths from the Word of God and through personal experience? The righteousness of God is revealed from faith to faith. Are you learning more about God than ever before? Is your faith increasing exponentially? These are the signs of a living faith in a living God.