A witness is someone called upon to provide evidence to validate a claim. Three key things a witness must bear in mind Firstly, a Christian witness tells what he or she knows. For you to be a good witness, it must be a person who speaks the truth. A good witness testifies of nothing but the truth. To be an effective witness you must know about Christ to others.
Secondly, a Christian witness shares what he or she has experienced. You must carry your own personal testimony to others. A person's best sermon is his or her own life.
Thirdly, being a witness means you must remain faithful and loyal to the end. We need to remain steadfast in the faith in spite of the challenges.
As a faithful Christian, you do not have to backtrack and backslide. We need not give excuses, the good news is that Jesus is aware of your shortcomings but promises that the Holy Spirit would work through your testimony, not your perfection.
In conclusion, we have been called to witness and we need to serve Him as a faithful witness.