Matthew Henry and continuators on Proverbs 12:6

6 The words of the wicked are to lie in wait for blood: but the mouth of the upright shall deliver them.

In the foregoing verse the thoughts of the wicked and righteous were compared; here their words, and those are as the abundance of the heart is. 1. Wicked people speak mischief to their neighbours; and wicked indeed those are whose words are to lie in wait for blood; their tongues are swords to those that stand in their way, to good men whom they hate and persecute. See an instance, Luke xx. 20, 21. 2. Good men speak help to their neighbours: The mouth of the upright is ready to be opened in the cause of those that are oppressed (ch. xxxi. 8), to plead for them, to witness for them, and so to deliver them, particularly those whom the wicked lie in wait for. A man may sometimes do a very good work with one good word.