'Sincerity' in the Bible

“Now, therefore, fear the Lord and serve Him in sincerity and in truth; remove the gods which your fathers served on the other side of the [Euphrates] River and in Egypt, and serve the Lord.

“My words will express the uprightness of my heart,And my lips will speak what they know with utter sincerity.

The Lord dealt with me according to my righteousness (moral character, spiritual integrity);According to the cleanness of my hands He has rewarded me.

“Hear this, O house of Jacob, you who are called by the name of IsraelAnd who come from the seed of Judah,You who swear [allegiance] by the name of the LordAnd invoke the God of Israel,But not in truth (sincerity) nor in righteousness [with moral and spiritual integrity].

Yet in spite of all this her treacherous sister Judah did not return to Me with her whole heart, but rather in [blatant] deception [she merely pretended obedience to King Josiah’s reforms],” declares the Lord.

“Roam back and forth through the streets of Jerusalem,And look now and take note.And look in her open squaresTo see if you can find a man [as Abraham sought in Sodom],One who is just, who [has integrity and moral courage and] seeks truth (faithfulness);Then I will pardon Jerusalem—[for the sake of one uncompromisingly righteous person].

Therefore, let us celebrate the feast, not with old leaven, nor with leaven of vice and malice and wickedness, but with the unleavened bread of sincerity and [untainted] truth.

This is our [reason for] proud confidence: our conscience testifies that we have conducted ourselves in the world [in general], and especially toward you, with pure motives and godly sincerity, not in human wisdom, but in the grace of God [that is, His gracious lovingkindness that leads people to Christ and spiritual maturity].

For we are not like many, [acting like merchants] peddling God’s word [shortchanging and adulterating God’s message]; but from pure [uncompromised] motives, as [commissioned and sent] from God, we speak [His message] in Christ in the sight of God.

I am not saying this as a command [to dictate to you], but to prove, by [pointing out] the enthusiasm of others, the sincerity of your love as well.

And we desire for each one of you to show the same diligence [all the way through] so as to realize and enjoy the full assurance of hope until the end,

Little children (believers, dear ones), let us not love [merely in theory] with word or with tongue [giving lip service to compassion], but in action and in truth [in practice and in sincerity, because practical acts of love are more than words].

Grace, mercy, and peace (inner calm, a sense of spiritual well-being) will be with us, from God the Father and from Jesus Christ, the Father’s Son, in truth and love.

For I was greatly pleased when [some of the] brothers came [from time to time] and testified to your [faithfulness to the] truth [of the gospel message], that is, how you are walking in truth.