Abu Dawud Book 2, Hadith Number 1365.

Chapter : The commandment of observing moderation in praying.

Narated By ‘Alqamah : ‘Aisha was asked about the actions of the Apostle of Allah (PBUH). Did he perform some actions exclusively on some particular days? She said: No, he performed his actions regularly. Which of you has the strength as much as the Apostle of Allah (PBUH) had?

Complete Translation of Sunan Abu-Dawud, Book 2: Prayer (Kitab Al-Salat): Detailed Injunctions about Ramadan