'Futile' in the Bible

Then the Pharisees [argued and] said to one another, “You see that your efforts are futile. Look! The whole world has gone [running] after Him!”

For even though they knew God [as the Creator], they did not honor Him as God or give thanks [for His wondrous creation]. On the contrary, they became worthless in their thinking [godless, with pointless reasonings, and silly speculations], and their foolish heart was darkened.

If those who are [followers] of the Law are [the true] heirs [of Abraham], then faith [leading to salvation] is of no effect and void, and the promise [of God] is nullified.

and again, “The Lord knows the thoughts of the [humanly] wise, that they are useless.”

and if Christ has not been raised, your faith is worthless and powerless [mere delusion]; you are still in your sins [and under the control and penalty of sin].

Therefore, my beloved brothers and sisters, be steadfast, immovable, always excelling in the work of the Lord [always doing your best and doing more than is needed], being continually aware that your labor [even to the point of exhaustion] in the Lord is not futile nor wasted [it is never without purpose].

But avoid foolish and ill-informed and stupid controversies and genealogies and dissensions and quarrels about the Law, for they are unprofitable and useless.

If anyone thinks himself to be religious [scrupulously observant of the rituals of his faith], and does not control his tongue but deludes his own heart, this person’s religion is worthless (futile, barren).