Albert Barnes Commentary Galatians 3:4

"Did ye suffer so many things in vain? if it be indeed in vain." — Galatians 3:4 (ASV)

Have you suffered so many things in vain? Paul reminds them of what they had endured on account of their attachment to Christianity. He assures them that if the opinions for which they had suffered were false, then their sufferings had been in vain.

These sufferings were of no use to them—for what advantage was it to suffer for a false opinion? The opinions for which they had suffered had not been those which they now embraced. They were not those connected with the observance of the Jewish rites.

They had suffered on account of their having embraced the gospel—the system of justification by a crucified Redeemer; and now, if those views were wrong, their sufferings had been wholly in vain. See this argument pursued at much greater length in 1 Corinthians 15:18, 19, 29-32.

If it is yet in vain. That is, "I trust it is not in vain. I hope you have not so far abandoned the gospel that all your sufferings on its behalf have been of no avail. I believe the system is true; and if true, and you are sincere Christians, it will not be in vain that you have suffered on its behalf, though you have gone astray. I trust that although your principles have been shaken, they have not been wholly overthrown, and that you will yet reap the reward of your having suffered so much on account of the gospel."