And straightway the work followed, bearing witness to his character. nothing; for the question is, whether each of them has set before us the zealousness of the man, and his having had the right opinion concerning Christ. But it is likely, that after sending his friends, he himself also came and said these things. And if Luke did not speak of the one, no more did Matthew of the other; and this is not the part of men disagreeing among themselves, but rather of those that are filling up the things omitted by one another. But see by another thing also how Luke has proclaimed his faith, saying that his servant “was ready to die.” Nevertheless, not even this cast him into despondency, neither did it cause him to give up: but even so he trusted that he should prevail. And if Matthew affirm Christ to have said, “I have not found so great faith, no, not in Israel,” and hereby to show clearly that he was not an Israelite; while Luke says, “He built our synagogue;” neither is this a contradiction. For it was possible for one, even though not a Jew, both to build the synagogue, and to love the nation.
Source: Homilies on the Gospel of St. Matthew (New Advent)