The evidence of salvation in a person is a changed life. Paul writes to the Thessalonians that after they received the Gospel and through the power of the Holy Spirit they became imitators of them (Paul and his travel companions) and imitators of Christ.
There are a number of times in the Bible where Paul tells his readers, "Imitate me". Most of the time he writes, "Imitate me and the Lord." He actually equates the two, he essentially says, "If you imitate me, then you imitate Christ." I don't think Paul is exalting himself by saying these things. I think he was simply saying, "Do as I do because I am imitating Christ." Imagine for one moment that your life was so dedicated to Christ that you could honestly tell others to imitate you what that would look like. How would that change the way you live your life? If you knew people were watching you and using you as an example what would you do different? What would I do different? Would I change the way I talk? Would I change the way I treat others? Would I change the way I drive? The list goes on...
The fact is, people are watching us and they are not impressed. It's a sad thing when I hear the reason someone does not want to be a Christian or attend church is because "they are all a bunch of hypocrites." They look at us and see we don't always practice what we preach. Our response is often, "Hey don't look at the actions of God's people, look to God." This is unfortunate that the people who supposedly represent Christ here on earth say, "Don't look at us, we are merely human and imperfect" (which is true). I know I long to be like Paul (and I am a long way from being like him) so I can say with an honest heart, "Imitate me because I am imitating Christ."
Random thought... Strive to be imitators of Christ; not for our benefit but for his glory.