What is a verse that St Matthew wrote himself?

Matthew, one of Jesus' twelve apostles, (also known as Levi the Tax collector) wrote the whole of the gospel of Matthew.

Some 40% of the content of his gospel is not found in any other gospel. For example, in the genealogy of Jesus that covers the first sixteen verses of his first chapter, Matthew uniquely traces Jesus ancestry through Jesus' adoptive father Joseph, whereas Luke records Jesus' natural genealogy.

Just one example of a unique verse is Matthew 1:17:

"Thus there were fourteen generations in all from Abraham to David, fourteen from David to the exile to Babylon, and fourteen from the exile to the Christ." (NIV)

Evidently Matthew spotted this numerical pattern, he formerly being a tax collector and therefore interested in numbers, and consequently made a note of this interesting fact which might subsequently serve as a memory aid for his readers.

Matthew recorded many of the words which Jesus spoke, such as the Sermon on the Mount in chapters 5 through 7 and Jesus denunciation of the religious leaders of His day in chapter 23. Even though these are Jesus' words, they are still Matthews in the sense that he recorded them. Of course the rest is Matthew's personal record of Jesus life (as well as other recorded sayings). Some use the idea of various sources to negate the individuality of Matthew's work. Matthew undoubtedly had personal knowledge of Jesus due to his discipleship, even if he did use other material in making his final 'edition' of his Gospel. In any case there is evidence that Matthew was the first to write, and that he did so in Aramaic, this Gospel being now lost, with the Greek text the only one to be preserved.

Almost certainly it seems Jesus Himself did no writing, although it is unlikely that He could not do so. All of Matthew's Gospel is thus Matthew's personal record of Jesus' life and teachings.

Until the author of the Book of Matthew is identified without any doubt, your question will remain un ed

The author of Matthew has been clearly identified beyond reasonable doubt. Considering the likely naming of a number of different authors, if the author was unknown the unanimous naming of Matthew as the author is telling. This unanimous naming of Matthew the former tax-collector (an unlikely author for a Gospel) clearly indicates he was considered as the only person possible to have authored it.

Considering the position of tax-collectors in Israel and the real animosity, it certainly would be unlikely for Matthew to be named as the author of a book he did not in fact write.