If people want to receive the gospel by some means other than "by hearing with faith," then that would constitute a rejection of faith as sufficient to bring about our justification before God. Paul uses Abraham as an example of someone who was justified by faith apart from meritorious works (Galatians 3:6).
There exists no type of good works that can enable us to obtain salvation from our sins (Galatians 3:21-25). The Apostle Paul's focus (in combating the Judaizers) extends beyond the Mosaic Law or any particular system of good works ("For if a law had been given which was able to impart life..."). He is arguing against seeking after justification by faith alone.