Gal 3:3b NET
"are you now trying to finish by human effort?"
"why are you now trying to become perfect by your own human effort?"
also some other paraphrase versions put it same way:
CEB Are you so irrational? After you started with the Spirit, are you now finishing up with your own human effort?
GW Are you that stupid? Did you begin in a spiritual way only to end up doing things in a human way?
AMP Are you so foolish and senseless? Having begun [your new life by faith] with the Spirit, are you now being perfected and reaching spiritual maturity by the flesh [that is, by your own works and efforts to keep the Law]?
The literal translation example ESV
Having begun by the Spirit, are you now being perfected by the flesh?