What Berachah did they give to the Am?
'Rashi': They blessed that Hashem fulfill their request to return from the land of their captivity.
What was the consequence of Hashem hearing their voice?
'Rashi': He returned them from their captivity.
'Rashi' (from Midrash Tehilim 108): Hashem acceded to Chizkiyah's request, and healed (pardoned) the nation.
Malbim: This corresponds to "li'M'on Kodsho", and "va'Tavo Sefilasam" - "la'Shamayim". This is like "v'Samu Es Shmi Al Bnei Yisrael" - Birkas Kohanim makes Hashem's name rest on Yisrael, that the Shechinah will be fixed in Me'on Kodsho (the Mikdash). He heard their voice about this, and put His name on Bnei Yisrael. "Va'Tavo Sefilasam... la'Shamayim" - via this He blessed His nation - "va'Ani Avarechem."
