For many in Judah were bound by oath to him, because he was the son-in-law of Shecaniah the son of Arah: and his son Jehohanan had taken the daughter of Meshullam the son of Berechiah as his wife.
Nehemiah is here finishing the wall of Jerusalem, and yet still has trouble created him by his enemies. I. Tobiah, and the other adversaries of the Jews, had the mortification to see the wall built up, notwithstanding all their attempts to hinder it. The wall was begun and finished in fifty-two days, and yet we have reason to believe they rested on the sabbaths, Neh 6:15.
Commenting on Nehemiah 6:15-19
For there were many in Judah sworn unto him,.... To Tobiah, who not only in a private manner corresponded with him by letters, but bound themselves by an oath to him to be true to his interest, and do as he should advise them: because he was the son in law of Shechaniah, the son of Arah; of a family that came up with Zerubbabel...
He was the son-in-law of Shechaniah - Previously to the coming of Nehemiah, the Jews seemed to be fast intermixing with the heathen, by intermarriages with Ashdodites, Ammonites, and Moabites; see Neh 13:23. Ezra had many evils of this kind to redress, (Ezr 9:3, etc.), chiefly among the common people, though there were both chiefs and priests in that trespass.