If we want to teach others and impart wisdom that we have gleaned in our lives, our actions can either back us up or disqualify what we are saying. It makes sense, then, that Paul also tells Timothy to live above reproach. To continue to live his life in a way that others will see and respect means that it will be easier for him to instruct the church and continue to correct their doctrine.
This whole section (4:6-16) is also applicable for most of us today in it’s reminders to continue to live with Christ the focus and centre of what we do, especially if we are in positions of leadership. However, the only way we can persevere and do all these things and act in confidence is remembering that we have our hope set in Christ and that it doesn’t matter what others may think or say. If we lead by example, it is easier for others to follow.