Verses 10-12: Ye observe days, and months, and times, and years. I am afraid of you, lest I have bestowed upon you labour in vain. Brethren, I beseech you, be as I am; for I am as ye are: ye have not injured me at all. Again, the Judaizers were convincing them, both Jew and Gentile, that they had to keep the Mosaic law to be saved. Unfortunately, to do so was to pervert the gospel of grace by adding works to it.
Paul also feels the need to let them know that he is not angry with them, and just wants the relationship restored that they once had which he will describe in the following verses. You can only imagine the horrible things that the Judaizers were telling them about Paul. Of course, as a pastor, I do not have to imagine.
Verses 13-15: Ye know how through infirmity of the flesh I preached the gospel unto you at the first. And my temptation which was in my flesh ye despised not, nor rejected; but received me as an angel of God, even as Christ Jesus. Where is then the blessedness ye spake of? for I bear you record, that, if it had been possible, ye would have plucked out your own eyes, and have given them to me. He goes on to remind them of the relationship that they used to have with each other before the Judaizers stepped in to ruin it. He also makes an interesting comment when he says my temptation which was in my flesh ye despised not, nor rejected. From his own statement in Galatians 6:11, he seems to be referring to his eyes or eyesight.
Some have even hypothesized that he was suffering from ophthalmia or a similar eye disease which was very prevalent in the first-century due to poor lighting that caused the eye to become inflamed and a mucus type leak. This may have been Paul's thorn in the flesh that he mentioned in 2 Corinthians 12:7.
Verses16-18: Am I therefore become your enemy, because I tell you the truth? They zealously affect you, but not well; yea, they would exclude you, that ye might affect them. But it is good to be zealously affected always in a good thing, and not only when I am present with you. He was warning them not to be offended because he was speaking truth to them. Unfortunately, the Judaizers had a lot of zeal in their appeals to them, but they were leading them the wrong way. He further tells them that what the Judaizers were trying to do was to alienate them from Paul to win them over to their side.