Pastor, I also studied engineering in college and learned the definition of work (any effort that uses up energy). If you were lying down on your bed and I came into your room and told you not to get up but to stay right there in bed while I asked you to answer a difficult math problem in your head that would take you a few minutes to solve, would you be doing work even though you were just lying there thinking? Would you not be using up energy in your brain while your were thinking? Is this not a mental work? The brain cells need energy to work even though it’s a small amount in contrast to physical labor. Thinking is a work. Believing is a work. Believing is the least of all works performed by a person. It is the least of all efforts a person can do on his part. Believing uses the least amount of energy of all thinking processes because it is done in an instant but it is still a work. Since believing is a work, believing is not what saves a person. It is the object of that faith that saves a person. This why God credits or immputes His righteousness to us that believe. Why does God have to do this? It is because our faith is not righteous. He is the Savior not our faith. Salvation is not by works, which includes faith, which is the least of all the works. There is no such thing as “saving faith.” It is all “saving Grace.”
Faith is not a work! Compare Romans 4:16 and Romans 11:6. God defines faith as being by GRACE. God then defines GRACE as the absence of WORKS!