Saving faith is our faith that God alone credits as righteousness. Synergists wrongly believe if we believe the "right" things, with the "right" intensity, God is compelled to save us. That of course is hogwash. Salvation is by grace. In other words our faith does not earn or merit salvation, it is but a filthy rag to God. He turns our worthless faith into righteousness. Our salvation does not depend on our willingness to be saved, or what we do (works) to be saved, but on God alone. He requires that we believe in the One He sent, but all that accomplishes is to be considered.
My thread #2 addresses this from the Word. Romans 4 makes clear faith is not a work worthy of a wage.