Psalms 12:2

2.Every man speaketh deceit. David in this verse sets forth that part of unrighteousness which is contrary to truth. He says that there is no sincerity or uprightness in their speech, because the great object upon which they are bent is to deceive. He next describes the manner in which they deceive, namely, that every man endeavors to ensnare his neighbor by flattery (257) He also points out the fountain and first cause of this, They speak with a double heart. This doubleness of heart, as I may term it, makes men double and variable in their speech, in order thereby to disguise themselves in different ways, (258) or to make themselves appear to others different from what they really are. Hence the Hebrew word חלקות, chalakoth, which denotes flattery, is derived from a word which signifies division. As those who are resolved to act truthfully in their intercourse with their neighbors, freely and ingenuously lay open their whole heart; so treacherous and deceitful persons keep a part of their feeling hidden within their own breasts, and cover it with the varnish of hypocrisy and a fair outside; so that from their speech we cannot gather any thing certain with respect to their intentions. Our speech, therefore, must be sincere in order that it may be as it were a mirror, in which the uprightness of our heart may be beheld.