I am afraid of you
Which shows the danger he apprehended they were in, by taking such large steps from Christianity to Judaism, and expresses the godly jealousy of the apostle over them; intimates he had some hope of them, and in the whole declares his great love and affection for them; for love is a thing full of care and fear:
lest I have bestowed upon you labour in vain;
in preaching the Gospel among them with so much diligence and constancy, though so many afflictions and pressures lay upon him. Faithful ministers of the word are laborious ones; and such an one was the apostle; and who indeed laboured more abundantly than the rest in all places wherever he came; and such will be concerned, as he was, lest their labours should be in vain, not to themselves, but to the souls of others, whose everlasting good and welfare they are seeking. But how is it that the apostle should fear that his labour in preaching the Gospel would be in vain, and become of no effect through their observance of days, months, times, and years? because that hereby the pure spiritual and evangelic worship of God was corrupted, they bringing into it that which God had removed, and so became guilty of will worship; their Christian liberty was infringed, and they brought into bondage, a deliverance from which the Gospel proclaims; the doctrine of free grace in pardon, justification, and salvation, was made void, they observing these things in order to procure them thereby; and it was virtually and tacitly saying, that Christ was not come in the flesh, which is the main article of the Gospel; for since these things had respect to him, and were to continue no longer than till his coming, to keep on the observation of them, was declaring that he was not come; which is in effect to set aside the whole Gospel, and the ministration of it; so that the apostle might justly fear, that by such a proceeding all his labour, and the pains he had took to preach the Gospel, and salvation by Christ unto them, would be in vain.