Proverbs 12:17-20,22 He that speaks truth shows forth righteousness: but a false witness deceit. There is that speaks like the piercings of a sword: but the tongue of the wise is health. The lip of truth shall be established for ever: but a lying tongue is but for a moment. Deceit is in the heart of them that imagine evil: but to the counsellors of peace is joy. Lying lips are abomination to the LORD: but they that deal truly are his delight. 

‘Speaks truth’ – Four uses of the tongue: Speaking truth (John 14:6). Speaking lies (1Tim. 4:1-2). Speaking cutting things (12:18; Jas. 3:1-18). Speaking blessing (12:19; Matt. 8:8).

‘The lip of truth shall be established for ever: but a lying tongue is but for a moment.’ The 7th prophecy in Proverbs (12:19) and it is unfulfilled. Two kinds of tongues and destinies (Jas. 3:1-18; 1Pet. 3:10-11).

‘But a lying tongue is but for a moment.’ Four examples of lying tongues judged: Ahab (1Kin. 22:30, 37); Hananiah (Jer. 28:2, 11); Gehazi (2Kin. 5:22-27) and Ananias and Sapphira (Acts 5:1-10).

‘Deceit is in the heart of them that imagine evil: but to the counsellors of peace is joy.’ Deceit is in the heart of those who devise evil, but joy is in the heart of those who give counsel of peace.

‘Delight’ – Seven things God delights in: People that deal truthfully (12:22). Just weights (11:1). People upright in their ways (11:20). Prayers of the upright (15:8). Lovingkindness, judgment, and righteousness in the earth (Jer. 9:24). The Messiah (Isa. 42:1). Israel (Isa. 62:4).