“And yet Jesus says that belief is a work”
Insofar as it is the only “work” required for salvation. Indeed one must have faith that God justifies the ungodly (Romans 4:5).
“Not every one that saith unto me, Lord, Lord, shall enter into the kingdom of heaven; but he that doeth the will of my Father who is in heaven.” - Matt. 7:21”
And around we go. What is the ultimate will of God for us? John 6:29 - Jesus answered, “The work of God is this: to believe in the one he has sent.”
So now you’re saying that righteousness IS of works?