1)
Whose hearts are broken?
1.
Radak: Yisrael's; they are sad in Galus.
2.
Malbim: Yisrael's; their hearts are broken over their afflictions.
2)
What is the meaning of "u'Mechabesh l'Atzevosam"?
1.
Malbim: He dresses their wounds, i.e. sadness in their hearts. In place of the sadness, they will be filled with Simchah and joy.
