Psalms 55:21

19 God will hear and humiliate them— the One enthroned for the ages— Selah because they do not change and they have no fear of God.

20 My companion attacks his friends; he violates his covenant.

His speech is smooth as butter, but war is in his heart. His words are softer than oil, yet they are swords unsheathed.

22 Cast your burden upon the LORD and He will sustain you; He will never let the righteous be shaken.

23 But You, O God, will bring them down to the Pit of destruction; men of bloodshed and deceit will not live out half their days. But I will trust in You.

Do read the surrounding verses too, because the context often says more than a single verse.

Compare

BSB
His speech is smooth as butter, but war is in his heart. His words are softer than oil, yet they are swords unsheathed.
KJV
The words of his mouth were smoother than butter, but war was in his heart: his words were softer than oil, yet were they drawn swords.
WEB
His mouth was smooth as butter, but his heart was war. His words were softer than oil, yet they were drawn swords.
ASV
His mouth was smooth as butter, But his heart was war: His words were softer than oil, Yet were they drawn swords.
DARBY
Smooth were the milky [words] of his mouth, but his heart was war; his words were softer than oil, yet are they drawn swords.
BLB
His mouth has been smoother than butter, and war [is] in his heart; his words have been softer than oil, and they [are] drawn swords.
ÅB
Hans munns ord er glatte som smør, men hans hjertes tanke er strid; hans ord er bløtere enn olje, og dog er de dragne sverd.
OTB
Hans ord var glattere enn smør,
Men hans hjerte var satt på krig;
Hans ord var mykere enn olje,
Men de var dragne sverd.
B1930
Hans munns ord er glatte som smør, men hans hjertes tanke er strid; hans ord er bløtere enn olje, og dog er de dragne sverd.

Study notes (Tyndale)

Original text and word study

Cross references