"Paul is impressing upon them that it is the hardships that he had to go through. It is the agony that he had to go through. It is the testing and proving of the genuineness of his faith that God put him through, and God approved. Because God kept using him effectively for the ministry of the gospel after having passed the test. It was not his physical performance. It was his faithfulness to stay true to Christ in the midst of hardship.
"We need to realize these things because we live in a day where Christians look to escape the hardship. Look for an easy way out. But in reality, the difficult way is God proving us. Proving the genuineness of our faith to trust Him through it all. Not knowing what He is going to do, or how He is going to do it, but trusting Him. That He is in charge. And He controls everything. That is our testimony."
So Paul is sharing his care over them as a mother, and his care over them as a father, showing that ministry is not just preaching and teaching, ministry is family. Caring for people as if they are family. Not in general. He had to become that. By the Spirit of God they became like his own kids, and he is calling this to their attention.
Whenever he uses that phrase became, he is making reference to something that they were not normally; but something they became by the Spirit of God. And this word imitator means: expression. You have become the expression of all the churches of God. Most people think the apostle Paul is way up there in status. He is talking about things we can never become, or never be like. But the reality of it is Paul is always sharing what is the normal Christian life. He presents himself as living the normal Christian life, which other people are to mimic. Paul had a different ministry - he was an apostle and wrote most of the New Testament. But he is ministering to people who have the same Jesus Christ in them as in himself. And he says, "You see the expression of Christ in me? Let that be the expression of Christ in you."
"It is important to understand this principle. It is one of the key principles, if not the key one for a believer to understand. Hardships come. Persecutions come from Satan. He tries to chase us to the point that we become weary in order that we quit, refuse to go on. But God is sufficient. That is what we are learning. That is what growth is. Growth is learning that God is sufficient. Christ and His grace are sufficient for all needs. No matter what Satan is doing. No matter how bad things get. We have a tendency to look at our lives and look for relief. There are a lot of ministries out there that offer relief from struggles and hardships. 'Live your best life now' and get on board with happiness. And in reality, as Paul told Timothy, all those who live godly in Christ Jesus shall suffer persecution. It is a promise. But God is sufficient."