Salvation is not by works; however, how can you be sure of your calling and election, without the evidence? One of the evidences that you have, in fact, been called (and elected before that), is that your life is characterised, not by sin, but by righteousness.demonstrate to whom? Read the text slowly... It is not for demonstration purposes... it is so that you shall not fall...
2 Peter 1:10
Wherefore the rather, brethren, give diligence to make your calling and election sure: for if ye do these things, ye shall never fall:
2 Pet. 1:10 (ESV) Therefore, brothers, be all the more diligent to confirm your calling and election, for if you practise these qualities you will never fall.
1 John 3:7-9 (EMTV)
7 Little children, let no one deceive you. Whoever practises righteousness is righteous, just as He is righteous.
8 He who practises sin is of the devil, for the devil has been sinning from the beginning. For this reason the Son of God appeared, that He might destroy the works of the devil.
9 No-one who has been born of God practises sin, because His seed abides in him; and he cannot keep on sinning, because he has been born of God.