For I have no one like him, who will be genuinely concerned for your welfare. (ESV)
How many people in your life would you describe as having genuine concern for other people's welfare? I would love to say that all people who claim the name of Christ would fit that description, but look at what Paul says, "I have no one like him." In other words, he was the exception not the rule. His love for others was remarkable.
Timothy had spent much time with the Apostle Paul. The more that we spend with someone the more we pick up the same kind of traits and behaviors. Thankfully, in this situation, Timothy picked up Paul's traits of love and concern for the church. Paul had planted churches all over the Roman Empire, and he had great concern for all of them.
In the Apostle Paul's second letter to the church at Corinth he describes the concern he has for all the churches:
2 Corinthians 11:28–29
 And, apart from other things, there is the daily pressure on me of my anxiety for all the churches.  Who is weak, and I am not weak? Who is made to fall, and I am not indignant? (ESV)
Paul's concern for the church at Philippi was a microcosm of his concern for all the churches. He had mentored this young man, Timothy, who had grown to share the same kind of concern for Philippi and all of God's churches. It is no surprise that there is no one quite like him. Paul was sending an extension of himself to this church at Philippi.
If Paul were here today would he be able to choose you to send as an encouragement to another church? Look to a great leader and allow them to mentor you to be that Timothy that the church needs.