Purity of motive — unmixed, undisguised, free from the fillers of pretense. Greek eilikrineia (sincerity, purity) literally means tested by sunlight — the image is of fine pottery held up to bright light to reveal whether it has been patched with wax (which would melt under heat). The sincere is what survives the sunlight test. Required of preaching (2 Cor 2:17: For we are not as many, which corrupt the word of God: but as of sincerity, but as of God), of love (1 Pet 1:22: see that ye love one another with a pure heart fervently), of life (Phil 1:10: that ye may be sincere and without offence till the day of Christ). Christian sincerity is not naivety or guilelessness in the social sense; it is the absence of hidden manipulative motive. The sincere Christian wants from his neighbor what he says he wants, says what he means, and does what he intends. He has stopped using people for ends they don't know about.