And yet the Bible also makes it clear that all of us will sin, whether or not we have Jesus. (Are you prepared to argue otherwise- that some Christians never sin and are perfect?) So are we all liars?
I believe the true followers of Jesus show the fruits of the Spirit and interact with the world as Christ did- in love and compassion, gentleness and humility. The way I see it, if my perfect savior came to earth loving prostitutes and tax collectors, healing the insane and ill, feeding people and preaching a gospel of love... then I am called to follow that path- to love all humanity, to heal wounds when I can, to take care of people's suffering when I'm able, and to always extend the Gospel of Christ through compassionate and loving action. I take my cue of how to preach the gospel of Christ by the methods Jesus himself used.
My life should be my testimony of being saved. My experience has been that no words are even needed. The mere act of extending peace, love, compassion, kindness, self-control, humility to others is the greatest witness to what God has wrought in my life... and I wait for God to bring me someone who has noticed this testimony and whom God has prepared to receive the gospel. When they ask me why I am so concerned with all humanity and nature, why I do not hate, why I will openly weep for the dead and suffering everywhere due to humankind's greed, fear, and hatred... I say because my God loves all life and God's creations are sacred, and my Savior called me to live a life of love and service. When they ask me how it is that I find joy and peace though I work in a field that studies all the evils of humanity (war, poverty, hatred), I say... because I have experienced God, and one pure moment in Divine Love changes a soul for eternity.