You don't witness because
1. You are afraid. you fear man, not God.
2. you are ashamed of the gospel
3. You tell yourself that if you let your light shine, they will some how understand, through your silent witness, that they need to ask Jesus
Christ to forgive their sins, and be their Lord.
You don't witness because you are
But the main reason that people don't witness, is because they keep waiting for the right timing.
If you have known someone for six months, it is time to make an opening.
The devil's biggest lie is not "never" but "tomorrow"