During one sermon in my youth, I heard someone describe the Christian path as continually upwards, getting closer and closer to God throughout one's lifetime. This hasn't been my experience, my path of faith has been more up and down, even falling completely off the mountain a time or two. And yet, the Spirit himself continues to to testify within my life.
My life is changed and continues to change, he has replaced the fear of God with family love, so that I can call God, my Father. I have other internal desires that come from God and that have become stronger over time, such as a hunger for God's word, a need to give to others, a desire to be with other Christians, a desire to know Christ better and to turn from sin. These desires are not from me, they are evidence of the Spirit speaking into my life. Through this testimony, I have assurance that I am a new creation, saved by God to live an abundant life. This is not my work, but God's work within me, evidence of his love and mercy and his gift of salvation through Christ. I have a changed worldview, a strong hope, a new heart. I forgive others because I have been forgiven much. I am moved to love others because of the great love that has been showered on me.