James 3:8

but the tongue can no one among men tame; it is an unsettled evil, full of death-bringing poison.

Psalm 140:3

They sharpen their tongues like a serpent; adders' poison is under their lips. Selah.

Romans 3:13

their throat is an open sepulchre; with their tongues they have used deceit; asps' poison is under their lips:

Ecclesiastes 10:11

If the serpent bite before enchantment, then the charmer hath no advantage.

Deuteronomy 32:33

Their wine is the poison of dragons, And the cruel venom of vipers.

Psalm 55:21

Smooth were the milky words of his mouth, but his heart was war; his words were softer than oil, yet are they drawn swords.

Psalm 57:4

My soul is in the midst of lions; I lie down among them that breathe out flames, the sons of men, whose teeth are spears and arrows, and their tongue a sharp sword.

Psalm 58:4

Their poison is like the poison of a serpent: they are like the deaf adder which stoppeth her ear;

Psalm 59:7

Behold, they belch out with their mouth; swords are in their lips: for who say they doth hear?

Psalm 64:3-4

Who have sharpened their tongue like a sword, and have aimed their arrow, a bitter word;

James 3:6

and the tongue is fire, the world of unrighteousness; the tongue is set in our members, the defiler of the whole body, and which sets fire to the course of nature, and is set on fire of hell.

Revelation 12:9

And the great dragon was cast out, the ancient serpent, he who is called Devil and Satan, he who deceives the whole habitable world, he was cast out into the earth, and his angels were cast out with him.

Treasury of Scripture Knowledge

Summary

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

General references

Bible References

An unruly

James 3:6
and the tongue is fire, the world of unrighteousness; the tongue is set in our members, the defiler of the whole body, and which sets fire to the course of nature, and is set on fire of hell.
Psalm 55:21
Smooth were the milky words of his mouth, but his heart was war; his words were softer than oil, yet are they drawn swords.
Psalm 57:4
My soul is in the midst of lions; I lie down among them that breathe out flames, the sons of men, whose teeth are spears and arrows, and their tongue a sharp sword.
Psalm 59:7
Behold, they belch out with their mouth; swords are in their lips: for who say they doth hear?
Psalm 64:3
Who have sharpened their tongue like a sword, and have aimed their arrow, a bitter word;

Full

Deuteronomy 32:33
Their wine is the poison of dragons, And the cruel venom of vipers.
Psalm 58:4
Their poison is like the poison of a serpent: they are like the deaf adder which stoppeth her ear;
Psalm 140:3
They sharpen their tongues like a serpent; adders' poison is under their lips. Selah.
Ecclesiastes 10:11
If the serpent bite before enchantment, then the charmer hath no advantage.
Romans 3:13
their throat is an open sepulchre; with their tongues they have used deceit; asps' poison is under their lips:
Revelation 12:9
And the great dragon was cast out, the ancient serpent, he who is called Devil and Satan, he who deceives the whole habitable world, he was cast out into the earth, and his angels were cast out with him.

General references

Matthew 15:18
but the things which go forth out of the mouth come out of the heart, and those defile man.