Well let's discuss that then. There are some scriptures that actually say it is.
John 6:29
Jesus answered, "The work of God is this: to believe in the one he has sent."
What is the work? It is believing or having faith in Jesus. So faith is a work.
Ephesians 2:8-9
For it is by grace you have been saved, through faith—and this is not from yourselves, it is the gift of God—not by works, so that no one can boast.
Salvation by Grace through Faith is a gift from God. Since this is not by works, faith is not our own doing, because if it was our own doing then then salvation would be by works.
Yes it is in us, we are the ones having faith, but God is the one who gives it.