1)
How were their ropes put on him?
1.
Rashi: He was incarcerated in his house, as if he was bound in ropes. Also Targum Yonasan is like this.
2.
Radak: It is as if they tied him in ropes, for he could not leave his house to go among them.
3.
Malbim: This is like it says below (4:8) "v'Hine Nasati Alecha Avosim v'Lo Sehafech mi'Tzidecha El Tzidecha." Since this was due to their sin, it is as if they put ropes on him.
2)
Since he must stay in his house, why must it say "v'Lo Setzei b'Socham"?
1.
Malbim: This is even if they will come to you.
