Matthew 6:7

But when ye pray, use not vain repetitions, as the heathens; for they think they shall be heard for their much speaking.

Romans 1:21

Because knowing God, they did not glorify him as God, neither were thankful, but became vain in their reasonings, and their foolish heart was darkened.

1 Peter 1:18

Seeing ye know ye were not redeemed with corruptible things, as silver and gold, from your vain conversation delivered by tradition from your fathers,

Treasury of Scripture Knowledge

Summary

For the customs of the people are vain: for one cutteth a tree out of the forest, the work of the hands of the workman, with the axe.

General references

Bible References

Customs

Matthew 6:7
But when ye pray, use not vain repetitions, as the heathens; for they think they shall be heard for their much speaking.
Romans 1:21
Because knowing God, they did not glorify him as God, neither were thankful, but became vain in their reasonings, and their foolish heart was darkened.
1 Peter 1:18
Seeing ye know ye were not redeemed with corruptible things, as silver and gold, from your vain conversation delivered by tradition from your fathers,

General references

Acts 16:21
being Jews, exceedingly trouble our city, And teach customs, which it is not lawful for us, being Romans, to receive, neither to observe.