'Vain' in the Bible

I went up [to Jerusalem] because of a [divine] revelation, and I put before them the gospel which I preach among the Gentiles. But I did so in private before those of reputation, for fear that I might be running or had run [the course of my ministry] in vain.

I do not ignore or nullify the [gracious gift of the] grace of God [His amazing, unmerited favor], for if righteousness comes through [observing] the Law, then Christ died needlessly. [His suffering and death would have had no purpose whatsoever.]”

Have you suffered so many things and experienced so much all for nothing—if indeed it was all for nothing?

I fear for you, that perhaps I have labored [to the point of exhaustion] over you in vain.