'Labor In Vain' in the Bible

“I am accounted wicked and held guilty;Why then should I labor in vain [to appear innocent]?

Unless the Lord builds the house,They labor in vain who build it;Unless the Lord guards the city,The watchman keeps awake in vain.

“They will not labor in vain,Or bear children for disaster;For they are the descendants of those blessed by the Lord,And their offspring with them.

Thus says the Lord of hosts,“The broad wall of Babylon will be completely overthrown and the foundations razedAnd her high gates will be set on fire;The peoples will labor in vain,And the nations become exhausted [only] for fire [that will destroy their work].”