1)
Why did he chase away Sanvalat's son-in-law?
1.
Rashi: It was lest Sanvalat, Tzorer ha'Yehudim, regularly come to Yerushalayim due to his son-in-law, to see who leaves and enters.
2.
Malbim: He could not lash him, for he was powerful. Since he could not force him, Hashem should punish him.
