Hadith: Do what you are capable of doing (regularly). By Allah, Allah never grows weary (of giving rewards) until you grow weary (of doing good deeds).

عن عائشة زوجِ النبي -صلى الله عليه وسلم-، أخبرته أنَّ الحَوْلاء بنت تُوَيت بن حبيب بن أسد بن عبد العُزَّى مرَّت بها وعندها رسول الله -صلى الله عليه وسلم-، فقلتُ: هذه الحَوْلاء بنت تُوَيت، وزعموا أنها لا تنام الليلَ، فقال رسول الله -صلى الله عليه وسلم-: «لا تنامُ الليلَ! خذوا مِن العمل ما تُطِيقون، فواللهِ لا يسأمُ اللهُ حتى تسأموا».
[صحيح] - [متفق عليه.]
المزيــد ...

`A'ishah, the wife of the Prophet, may Allah’s peace and blessings be upon him, reported: "Al-Hawlaa bint Tuwayt ibn Habeeb ibn `Abdul-`Uzza passed while I was sitting with the Messenger of Allah, may Allah’s peace and blessings be upon him. So I (`A'ishah) said: 'This is al-Hawlaa bint Tuwayt, and they claim that she does not sleep at night.' Upon hearing this, the Messenger of Allah, may Allah’s peace and blessings be upon him, said: 'She does not sleep at night! Do what you are capable of doing (regularly). By Allah, Allah never grows weary (of giving rewards) until you grow weary (of doing good deeds).”

As al-Hawlaa bint Tuwayt passed by `A'ishah, `A'ishah told the Prophet, may Allah’s peace and blessings be upon him, that this woman's name was al-Hawlaa bint Tuwayt and that she used to pray all night without sleeping at all. The Prophet, may Allah’s peace and blessings be upon him, condemned this act and said: "Do what you are capable of doing." Thus, the Prophet, may Allah's peace and blessings be upon him, ordered that woman to stop the tedious act that she was doing as she could find it difficult and become incapable of continuing it in the future. Then the Prophet, may Allah's peace and blessings be upon him, ordered that people should do only acts which they are capable of for "Allah will never grow weary until you grow weary." This means that Allah, may He be Glorified and Exalted, rewards people according to their acts of worship. When a slave continues to do a good deed, then Allah continues to reward him for that. However, if the slave grows weary of and bored with this act of worship, and consequently abandons it, then Allah will stop the reward of that particular act. This is because people are rewarded for their deeds, so whoever stops a specific deed, the reward of that particular deed will stop if that deed is stopped for no valid excuse such as sickness or travel. This is the most correct interpretation of "growing weary" that is understood from the apparent meaning of the Hadith as a description of Allah the Exalted. Allah's "malal" (boredom/weariness), is not similar to people's "malal", for ours means fatigue, tiredness, and laziness whereas that of Allah is an attribute that is exclusive to Him in a way that befits His majesty. Indeed Allah, may He be Glorified and Exalted, does not feel tired or lazy.