For he loveth our nation This was, no doubt, a commendation given him by the Jews on account of his piety: [1] for his love of a nation universally hated could proceed only from zeal for the Law, and from reverence for God. By building a synagogue, he showed plainly that he favored the doctrine of the Law. The Jews had therefore good grounds for saying that, as a devout worshipper of God, he had claims on Christ for receiving such a favor. They discover, at the same time, a marvellous stupidity in admitting, by their own acknowledgment, that a Gentile possesses that grace of God which they despise and reject. If they consider Christ to be the minister and dispenser of the gifts of God, why do they not receive the grace offered to them before bringing foreigners to enjoy it? But hypocrites never fail to manifest such carelessness and presumption, as not to hesitate to look upon God as under some sort of obligations to them, and to dispose of his grace at their pleasure, as if it were in their own power; and then, when they are satisfied with it, or rather because they do not deign to taste it, they treat it as useless, and leave it to others.

Footnotes

1 - "Il n' y a point de doute que les Juifs recommandent cest homme pour l'affection et le bon zele qu'il avoit a la crainte de Dieu." -- "There is no doubt that the Jews recommend this man for the affection and the good zeal which he had for the fear of God."

He loveth our nation - He is a warm friend to the Jews; and has given a full proof of his affection to them in building them a synagogue. This he had done at his own proper charges; having no doubt employed his own men in the work.

For he loveth our nation,.... The Jewish nation, which was Christ's nation, as well as theirs, he being a Jew; see John 18:35. This they mention as an argument to induce him to have a regard to the centurion, though he was a Gentile; since he was a friend of the Jews, and well affected and disposed to them, which was very rare: it was not common for the Gentiles to love the Jews, any more than the Jews the Gentiles; there was an hatred, yea, an enmity between them; but this man, very likely, was a proselyte to their religion, as the following instance seems to show:
and he hath built us a synagogue; at his own private charge, and by the assistance of his soldiers under him, whom he might employ in this work: sometimes a single person built a synagogue at his own expense, and gave it to the citizens; of which the Jews say, (o).
"if a man builds an house, and afterwards devotes it to a synagogue, it is as a synagogue.''
(o) Piske Harosh Megilia, c. 4. art. 1.

loved our nation--Having found that "salvation was of the Jews," he loved them for it.
built, &c.--His love took this practical and appropriate form.