Text

For there is no truth in his mouth; their inward part is a yawning gulf; an open grave is their throat; they will make smooth their tongue.

Rashi

For there is no truth in his mouth

They look like lovers, and they are enemies.

Their inward part is a yawning gulf

Their thoughts are deceit.

An open grave is their throat

To swallow the toil of others like the grave that swallows the body.

They will make smooth

Words of smoothness.

Ibn Ezra

For there isn't in his mouth

In the mouth of each one of them; like (Jeremiah 31:14): Weeps for her children; she has refused to be comforted, because he is not. And ...

Their inward part

That is the heart which is concealed.

A yawning gulf

...

An open grave

An immediate disaster.

They will make smooth

From the root of (Genesis 27:11): ...