WHO is a true Witness?
One who believes that Jesus is Lord, and God, come in the flesh for sinful men, and does his/her best to teach the truth to others as the Holy ghost allows.
If you are a beleiver, then you also would have the same love and compassion for your family, friends, and YES, the nonbelievers, too, even if they reject the word.
Jesus told us to judge NO ONE even those who do not believe, but to love all people.
You said the bible knows nothing of solitary religion. I disagree with that, for Jesus wants us to have a personal deep intimate relationship with God WITHOUT man's institutions standing in the way.
Tehre is something for going to church and worshipping together with others, if you can find a good spirit filled church. But such things are not necessary.
You can also find yourself trapped by man's false teachings, churches and cults who do not know their bible from the NATIONAL ENQUIRER, and Jesus wants us to get away form that, to have a relationship without being bound by the chains of Satan's lies.
Sweetests love to all of you in the name of the Father, Son, and Holy Ghost!