"They"? which "they" are you talking about?They changed faith into a work. Ephesians 2:8-9 explicitly says "not of yourselves." The JW NWT Romans 4:3,". . . Abraham exercised faith in Jehovah, and it was counted to him as righteousness.”
But WHAT is not of ourselves? The faith? or the salvation? If Jesus Christ was given to us for our salvation, that certainly is "not of ourselves". We are responsible for His death, but not for His coming; not for His sacrifice for our benefit.
There is both the idea that we are saved before we believe (Jesus died even while we were yet sinners) and the idea that we are saved because we believe (believe in the Lord Jesus Christ, and you WILL be saved). Maybe there are two parts to salvation?
Maybe we're splitting hairs unnecessarily.