Why Do Professions of Faith? (1 Timothy 6:12)

Paul exhorts Timothy to fight the good fight.  The motivation for this fight is that Timothy will then be able to take hold of eternal life.  So, does this mean that Timothy needs to work really hard to get to the goal of heaven or to receive the blessings of heaven? What does Timothy standing in the midst of the witnesses have to do with this this good fight?  What implications can we draw from this public testimony as well?