The lying lips and the deceitful tongue belong -- not to an external enemy—are powerful enemies in Scripture. As Isaiah wrote in Isaiah 6:5, Paul wrote in Romans 7:23-25, and James wrote in his epistle (James 3:5-9.) Whether it is the tongue of another person or our own tongue, tongues are hard to control. They even war against their owners.
Whether David speaks of deliverance from his own tongue or from the tongues of others, deliverance is necessary.
1In my distress I cried unto the LORD, and he heard me.
2Deliver my soul, O LORD, from lying lips, and from a deceitful tongue.
3What shall be given unto thee? or what shall be done unto thee, thou false tongue?
4Sharp arrows of the mighty, with coals of juniper.
5Woe is me, that I sojourn in Mesech, that I dwell in the tents of Kedar!
6My soul hath long dwelt with him that hateth peace.
7I am for peace: but when I speak, they are for war.