James 3:8

but no one can subdue the tongue. It is an uncontrollable [source of] evil and full of deadly poison.

Romans 3:13

[Psa. 5:9 says], "Their throats are like open graves [i.e., they are foul-mouthed]. They have spoken deceitfully." [Psa. 90:3 says], "There is snake venom under their lips [i.e., their words are deadly]."

James 3:6

And the tongue is [like] a fire [i.e., like that spark]. [For] the tongue, as a part of the body, is [like] the world of evil. It corrupts the entire life [of a person] and inflames the course of nature itself [i.e., it affects a person throughout his whole earthly existence], and is ignited by hell itself [i.e., the evil produced by the fiery tongue has hell as its source and destiny].

Revelation 12:9

Then the great dragon was thrown out [of heaven]; he is the snake from ancient times who is [also] called "the Devil," and "Satan," the deceiver of the entire world. He was thrown down to earth along with his angels.

Treasury of Scripture Knowledge

Summary

But the tongue can no man tame; it is an unruly evil, full of deadly poison.

An unruly

General references

Bible References

An unruly

James 3:6
And the tongue is [like] a fire [i.e., like that spark]. [For] the tongue, as a part of the body, is [like] the world of evil. It corrupts the entire life [of a person] and inflames the course of nature itself [i.e., it affects a person throughout his whole earthly existence], and is ignited by hell itself [i.e., the evil produced by the fiery tongue has hell as its source and destiny].

Full

Romans 3:13
[Psa. 5:9 says], "Their throats are like open graves [i.e., they are foul-mouthed]. They have spoken deceitfully." [Psa. 90:3 says], "There is snake venom under their lips [i.e., their words are deadly]."
Revelation 12:9
Then the great dragon was thrown out [of heaven]; he is the snake from ancient times who is [also] called "the Devil," and "Satan," the deceiver of the entire world. He was thrown down to earth along with his angels.

General references

Matthew 15:18
But the things that come out of a person's mouth come from his heart. These are what [spiritually] corrupt a person.