Matthew Henry's Complete Bible Commentary

Verse 9

Here is, 1. Hypocrisy designing ill. It is not only the murderer with his sword, but the hypocrite with his mouth, that destroys his neighbour, decoying him into sin, or into mischief, by the specious pretences of kindness and good-will. Death and life are in the power of the tongue, but no tongue more fatal than the flattering tongue. 2. Honesty defeating the design and escaping the snare: Through knowledge of the devices of Satan shall the just be delivered from the snares which the hypocrite has laid for him; seducers shall not deceive the elect. By the knowledge of God, and the scriptures, and their own hearts, shall the just be delivered from those that lie in wait to deceive, and so to destroy, Romans 16:18, 16:19. MHBCC 640.10