'Insincere' in the Bible

their hearts were insincere toward Him,and they were unfaithful to His covenant.

Like a [common] clay vessel covered with the silver dross [making it appear silver when it has no real value]Are burning lips [murmuring manipulative words] and a wicked heart.

The refining pot is for silver and the furnace for gold [to separate the impurities of the metal],And each is tested by the praise given to him [and his response to it, whether humble or proud].

Some of those who are [spiritually] wise and have insight will fall [as martyrs] in order to refine, to purge and to make those among God’s people pure, until the end time; because it is yet to come at the time appointed [by God].

Test yourselves to discover whether you are true believers: put your own selves under examination. Or do you not know that Jesus Christ is within you, unless you are insincere?

But I trust that you will recognize that we are not insincere.

The former proclaim the Messiah because they are selfishly ambitious and insincere, thinking that they will stir up trouble for me during my imprisonment.

Deacons likewise [must be] dignified, not insincere, not devoted to much wine, not fond of dishonest gain,