Nowhere does the Bible say to trust in the finished work of redemption. That is a Protestant saying. Protestants number in the high millions and thus they are not of the narrow path or way. They are the second largest denomination in the world. Jesus said narrow is the way that leads unto life and FEW be there that find it (Matthew 7:14).
I was struck by something.
When another becomes your everything, ones focus is what upsets the other or brings them joy is a driver of ones own behaviour.
My brother, an insecure quiet man got married. For the first time in his life, he was very careful what he said, how he said it and what his wife thought as a result. I had never seen this before in him. How I felt based on what he said, meant zero throughout my life with him.
So when the statement "If you believe in Jesus" is said this is emotionally implying everything in Jesus's heart is ones own heart, it is inter-twinned with ones own heart.
See the picture of the apostles, uneducated men, picked by Jesus and following Him, giving up everything to sit at his feet and learn. In a true way their following was root and branch following, walking with Jesus town to town. When Jesus said to them come follow me, it was not believe my words alone, but physically follow me.
In our modern world of ideas where we live as individuals, cut off from others, but going to work with a small group and home with family, the following of Jesus is restricted to church visits, house group, and personal reading probably. It is easy then to say the difference is just the words, belief, that matter. Often the lack of friendships and community, one to one engagement is so superficial you can be a recluse and still be thought of as a normal human being.
Which version of faith fits to the recluse? Open loving transformation or a belief system that helps reassure them while they hide away?
God bless you