Albert Barnes Commentary Galatians 4:11

"I am afraid of you, lest by any means I have bestowed labor upon you in vain." — Galatians 4:11 (ASV)

I am afraid of you, and so on. I have fears concerning you. His fears were that they had no genuine Christian principle. They had been so easily perverted and turned back to the servitude of ceremonies and rites, that he was apprehensive that there could be no real Christian principle in them. What pastor has not often had such fears of his people when he sees them turn to the weak and beggarly elements of the world, or when, after having run well, he sees them become the slaves of fashion, or of some habit inconsistent with the simplicity of the gospel?

The phrase "afraid of you" means "I fear concerning you."