Just like most parents would say its not their will to deny their children desert after a meal. But it would become their will if they were to do that for disciplinary reasons. The same thing here. Good works are God's will but they are not God's will as justifying your salvation, which is the issue that this verse was addressing. Salvation is by grace alone received not by works but by faith.
Good works are the product of salvation.
They are not the source of it. Good works are produced by the working of Christ within the saved person and motivated by our love and gratituted to Him. The will of the Father is that we accept and preach salvation by faith in the finished work of Christ's shed blood.