Sunan an-Nasa'i 5035
It was narrated from 'Aishah that:
The Prophet [SAW] entered upon her and there was a woman with her. He said: "Who is this?" She said: "So-and-so; she does not sleep"- she mentioned her excessive praying. The Prophet [SAW] said: "Keep quiet. You should do what you are able to, for by Allah, Allah, the Mighty and Sublime, does not get tired. The most beloved religion to Him is that in which a person persists."
أَخْبَرَنَا شُعَيْبُ بْنُ يُوسُفَ عَنْ يَحْيَى وَهُوَ ابْنُ سَعِيدٍ عَنْ هِشَامِ بْنِ عُرْوَةَ أَخْبَرَنِي أَبِي عَنْ عَائِشَةَ  أَنَّ النَّبِيَّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ دَخَلَ عَلَيْهَا وَعِنْدَهَا امْرَأَةٌ فَقَالَ مَنْ هَذِهِ قَالَتْ فُلَانَةُ لَا تَنَامُ تَذْكُرُ مِنْ صَلَاتِهَا فَقَالَ مَهْ عَلَيْكُمْ مِنْ الْعَمَلِ مَا تُطِيقُونَ فَوَاللَّهِ لَا يَمَلُّ اللَّهُ عَزَّ وَجَلَّ حَتَّى تَمَلُّوا وَكَانَ أَحَبَّ الدِّينِ إِلَيْهِ مَا دَامَ عَلَيْهِ صَاحِبُهُ