Matthew 6:7

And when you pray, do not use worthless repetitions like the [unconverted] Gentiles, for they think their lengthy, repetitious wording [in prayer] is more likely to be heard [by God].

Romans 1:21

Now they knew who God was, but they did not honor Him as God or thank Him [for their blessings]. Instead they engaged in their useless speculations and their foolish minds were filled with [spiritual] darkness.

1 Peter 1:18

You [should] know that you were bought back [from Satan], from your useless way of life, inherited from your forefathers, not with such perishable things as silver and gold,

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
And when you pray, do not use worthless repetitions like the [unconverted] Gentiles, for they think their lengthy, repetitious wording [in prayer] is more likely to be heard [by God].
Romans 1:21
Now they knew who God was, but they did not honor Him as God or thank Him [for their blessings]. Instead they engaged in their useless speculations and their foolish minds were filled with [spiritual] darkness.
1 Peter 1:18
You [should] know that you were bought back [from Satan], from your useless way of life, inherited from your forefathers, not with such perishable things as silver and gold,

General references

Acts 16:21
and they are teaching people to observe customs which we Romans are not permitted to accept or practice."