Urwah narrates from Sayyidah Aishah (may Allah be pleased with her) that the Prophet (peace and blessings be upon him) was in the mosque one day; he (peace and blessings be upon him) led the people in prayer, then the next night he led them in prayer again, and more people gathered. Then on the third or fourth night the Prophet (peace and blessings be upon him) did not come out to them. When morning came, he (peace and blessings be upon him) said: "I saw what you did, but I did not come out for fear that it would be made obligatory upon you." The narrator said: This was in Ramadan.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 4601