It is narrated from Hazrat Abu Huraira (may Allah be pleased with him) that the Holy Prophet (peace and blessings be upon him) said: When you lead the prayer as an imam, make the prayer light, because among those praying behind you are the elderly, the weak, and those with needs.
Hadith Referenceمسند احمد / مسند المكثرين من الصحابة / 10793