Testimony and witness is important to encourage and strengthen because the devil loves to make us feel "unique" in our suffering and trials. I know sometimes I get in the "nobody knows the troubles I've seen" mode and feel very alone and misunderstood. When I hear someone else's testimony, it somehow makes me feel stronger and able to withstand the enemy just knowing that I am not alone. Revelation 12:11 tells us our testimony is the key to being an overcomer - "And they have conquered him by the blood of the Lamb and the word of their testimony, for they loved not their lives unto death. Jesus as the faithful witness encourages us because he is the perfect overcomer and he was tested just like we are and was tempted just like we are. Scriptures tells us he was fully man and as such, he felt the same temptations and pain that we do - and he overcame it! I think our fear to be clear witnesses in this culture in this culture is plain and simple - we seek confirmation and approval from man sometimes more than from God, and the fear of disapproval or alienation from our peers keeps us from stepping out.