It is narrated from Abu Huraira (may Allah be pleased with him) that the Prophet (peace be upon him) said: "The imam is responsible for the prayer of those who follow him, and the muezzin is trustworthy. Allah has guided the imams and forgiven the muezzins."
Hadith Referenceمسند الإمام الشافعي / كتاب الصلاة / 292
Hadith Takhrijاخرجه احمد: 2/ 419 ـ وعبدالرزاق: 1839 ۔ والبيهقي : 430/1 وفي المعرفة السنن والآثار له (600)۔ وصححه ابن خزيمة: 1531 - وابن حبان: 1672۔