Galatians 4:12-16

I plead with you, brothers, become like me, for I became like you. You have done me no wrong.

(v12, NIV)

Paul is telling them to imitate him. Paul gives this instruction in 1 Corinthians as well.

I urge you, then, be imitators of me.

(1 Corinthians 4:16, ESV)

Be imitators of me, as I am of Christ.

(1 Corinthians 11:1, ESV)

Paul is living a life and trying to lead by example. We are to be imitators of Jesus, but it is not wrong to have intermediary goals. Paul is an imitator of Christ, so imitating Paul would also an attempt to imitate Christ in a sense. Paul also notes that he became like them. It almost doesn't make sense for them to become like Paul if he is becoming like them. If they are to become like Paul and Paul is becoming like them, does that mean that they are to become like themselves?

Though I am free and belong to no man, I make myself a slave to everyone, to win as many as possible. To the Jews I became like a Jew, to win the Jews. To those under the law I became like one under the law (though I myself am not under the law), so as to win those under the law. To those not having the law I became like one not having the law (though I am not free from God's law but am under Christ's law), so as to win those not having the law. To the weak I became weak, to win the weak. I have become all things to all men so that by all possible means I might save some. I do all this for the sake of the gospel, that I may share in its blessings.

(1 Corinthians 9:19-23, NIV)

Paul becomes like them in order to win them over to Christ. They are to mirror this same act of Paul by becoming like others in order to win them over to Christ.

As you know, it was because of an illness that I first preached the gospel to you. Even though my illness was a trial to you, you did not treat me with contempt or scorn. Instead, you welcomed me as if I were an angel of God, as if I were Christ Jesus himself. What has happened to all your joy? I can testify that, if you could have done so, you would have torn out your eyes and given them to me. Have I now become your enemy by telling you the truth?

(v13-16, NIV)

Paul's preaching to them initially was because of some sort of illness. This may be the thorn in Paul's flesh as he mentions in 2 Corinthians 12:7. This illness was even a burden to those at the church in Galatia as well. Even though it was a hindrance to them, they warmly welcomed Paul. However, their initial joy and welcoming Paul is contrasted with their current turning away from the Gospel which Paul had preached to them. At that time, they were so on fire for God that they would have even torn out their eyes for Paul. How many people are you willing to tear your eyes out for? That shows their love for Paul. However, their love did not remain for some reason, and they have even become Paul's enemy in a sense. You can feel Paul's frustration and utter confusion with their actions.