What does Nehemiah 6:18 mean?

A lot of people in Judah had promised to support Tobiah, because he was connected to them by marriage—he was the son-in-law of Shecaniah, son of Arah, and his own son Jehohanan had married the daughter of Meshullam, son of Berechiah. Nehemiah 6:18 - Modern Text Bible

(This verse explains why Tobiah had influence in Judah: he was tied to important families through marriage, making him hard to oppose.)