When John the Baptist saw the Pharisees and Sadducees coming to his baptism, he had some harsh words for them.  He knew coming to observe him was insincere.  One thing he said that was not so harsh though was, 

Bear fruit in keeping with repentance. (Matt 3:8 ESV throughout)

This is helpful for anyone.  His point was that no birthright or position, however lofty or admirable, was going to be enough to please God.  Those with the best social standing still need to repent.  And repentance, that turning from sin toward God with a new attitude toward both, is going to be visible.  One passage that shows us the contrast of a pre/post repentance life is Gal 5:19-24.

¹⁹ Now the works of the flesh are evident: sexual immorality, impurity, sensuality, ²⁰ idolatry, sorcery, enmity, strife, jealousy, fits of anger, rivalries, dissensions, divisions, ²¹ envy, drunkenness, orgies, and things like these. I warn you, as I warned you before, that those who do such things will not inherit the kingdom of God. ²² But the fruit of the Spirit is love, joy, peace, patience, kindness, goodness, faithfulness, ²³ gentleness, self-control; against such things there is no law. ²⁴ And those who belong to Christ Jesus have crucified the flesh with its passions and desires.

Another helpful passage is Col 1:9-11,

⁹ And so, from the day we heard, we have not ceased to pray for you, asking that you may be filled with the knowledge of his will in all spiritual wisdom and understanding, ¹⁰ so as to walk in a manner worthy of the Lord, fully pleasing to him: bearing fruit in every good work and increasing in the knowledge of God; ¹¹ being strengthened with all power, according to his glorious might, for all endurance and patience with joy.

Finally, Hebrews 13:15 adds a bit more.

Through him then let us continually offer up a sacrifice of praise to God, that is, the fruit of lips that acknowledge his name.

May our lives be full of good fruit, evidence that we have changed our minds, attitudes and hearts concerning sin and turned wholeheartedly toward God in Christ.