Sahih Bukhari Volume 2, Book 19, Hadith 1152

قَالَ وَقَالَ عَبْدُ اللَّهِ بْنِ مَسْلَمَةَ عَنْ مَالِكٍ، عَنْ هِشَامِ بْنِ عُرْوَةَ، عَنْ أَبِيهِ، عَنْ عَائِشَةَ ـ رضى الله عنها ـ قَالَتْ كَانَتْ عِنْدِي امْرَأَةٌ مِنْ بَنِي أَسَدٍ فَدَخَلَ عَلَىَّ رَسُولُ اللَّهِ صلى الله عليه وسلم فَقَالَ ‏"‏ مَنْ هَذِهِ ‏"‏‏.‏ قُلْتُ فُلاَنَةُ لاَ تَنَامُ بِاللَّيْلِ‏.‏ فَذُكِرَ مِنْ صَلاَتِهَا فَقَالَ ‏"‏ مَهْ عَلَيْكُمْ مَا تُطِيقُونَ مِنَ الأَعْمَالِ، فَإِنَّ اللَّهَ لاَ يَمَلُّ حَتَّى تَمَلُّوا ‏"‏‏

Narrated By 'Aisha : A woman from the tribe of Bani Asad was sitting with me and Allah's Apostle (p.b.u.h) came to my house and said, "Who is this?" I said, "(She is) So and so. She does not sleep at night because she is engaged in prayer." The Prophet said disapprovingly: Do (good) deeds which is within your capacity as Allah never gets tired of giving rewards till you get tired of doing good deeds."