Galatians 4:20 shows Paul's perplexity and desire to change his tone — directly parallel to his fear in 4:11 that he labored in vain.

Galatians 5:2-4 reveals the specific cause of Paul's fear: if they accept circumcision, they fall from grace, making his labor vain.

In Galatians 2:2, Paul uses the identical phrase 'run in vain' regarding his gospel presentation to the Jerusalem leaders, showing a recurring worry.

Galatians 5:10 expresses confidence in the Lord, contrasting with the fear of labor in vain. Paul moves from uncertainty to assurance.

2 John 1:8 warns against losing what has been worked for, echoing Paul's anxiety about wasted effort among believers.

1 Thessalonians 3:5 shows Paul's identical fear that the tempter's work would make his labor vain, a close parallel.

In Philippians 2:16, Paul hopes he did not 'run in vain or labor in vain,' using the same phrase as his concern for the Galatians.

In 2 Corinthians 12:21, Paul fears mourning over unrepentant sin, reinforcing the concern that his labor could be in vain.

In 2 Corinthians 12:20, Paul expresses a similar fear of finding sin among believers, echoing the same anxiety that his work might be wasted.

2 Corinthians 11:2 expresses Paul's divine jealousy and fear of the church being led astray — similar to his fear of laboring in vain in Galatians.

2 Corinthians 11:2 expresses Paul's divine jealousy and fear of the church being led astray — similar to his fear of laboring in vain in Galatians.

1 Corinthians 15:58 assures that labor in the Lord is not in vain, directly countering Paul's fear here with a promise.

Isaiah 49:4 has the servant lamenting 'I have labored in vain,' a direct OT parallel to Paul's fear of wasted effort.

2 Corinthians 6:1 warns against receiving grace in vain. Paul's fear in Galatians mirrors this same concern for fruitless ministry.

Colossians 1:23 conditions Paul's labor on the believer's continued faith. It explains what prevents labor from being in vain.

In Leviticus 26:20, labor in vain is a covenant curse. Paul fears his spiritual labor might suffer the same futility due to the Galatians' disobedience.

1 Thessalonians 2:1 affirms that Paul's visit was not in vain. This positive assertion contrasts with the fear in Galatians.