Galatians 4:18

18.But it is good to be the object of jealousy. It is hard to say whether this refers to himself or to the Galatians. Good ministers are exhorted to cherish holy jealousy in watching over the churches,

“that they may present them as a chaste virgin to Christ.”
(2 Corinthians 11:2.)

If it refers to Paul, the meaning will be: “I confess that I also am jealous of you, but with a totally different design: and I do so as much when I am absent as when I am present, because I do not seek my own advantage.” But I am rather inclined to view it as referring to the Galatians, though in this case it will admit of more than one interpretation. It may mean: “They indeed attempt to withdraw your affections from me, that, when you are thrown destitute, you may go over to them; but do you, who loved me while I was present, continue to cherish the same regard for me when I am absent.” But a more correct explanation is suggested by the opposite senses which the word ζηλοῦσθαι bears. As, in the former verse, he had used the word jealous in a bad sense, denoting an improper way of accomplishing an object, so here he uses it in a good sense, denoting a zealous imitation of the good qualities of another. By condemning improper jealousy, he now exhorts the Galatians to engage in a different sort of competition, and that, too, while he was absent.