'Aisha (may Allah be pleased with her) says:
"Messenger of Allah ﷺ once came home, a woman was present at that time. Messenger of Allah ﷺ inquired. 'Who is this woman?' I replied: 'This is a certain woman who does not sleep at night'. Messenger of Allah ﷺ said: 'One should observe only that amount of nawaafil which one can bear. I swear an oath that Allah Ta'aala does not fear the granting of rewards, till you begin to fear the observance of deeds'. 'Aisha (may Allah be pleased with her). 'Anha says: 'The most beloved deed of Messenger of Allah ﷺ were those that were practised continuously.

حَدَّثَنَا هَارُونُ بْنُ إِسْحَاقَ، قَالَ: حَدَّثَنَا عَبْدَةُ، عَنْ هِشَامِ بْنِ عُرْوَةَ، عَنْ أَبِيهِ، عَنْ عَائِشَةَ، قَالَتْ: دَخَلَ عَلَيَّ رَسُولُ اللهِ ﷺ وَعِنْدِي امْرَأَةٌ، فَقَالَ: مَنْ هَذِهِ؟ قُلْتُ: فُلانَةُ لا تَنَامُ اللَّيْلَ، فَقَالَ رَسُولُ اللهِ ﷺ: عَلَيْكُمْ مِنَ الأَعْمَالِ مَا تُطِيقُونَ، فَوَاللَّهِ لا يَمَلُّ اللَّهُ حَتَّى تَمَلُّوا، وَكَانَ أَحَبَّ ذَلِكَ إِلَى رَسُولِ اللهِ ﷺ الَّذِي يَدُومُ عَلَيْهِ صَاحِبُهُ.