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"Verily, your Lord knows that you do stand (to pray at night) a little less than two-thirds of the night, or half the night, or a third of the night, and so do a party of those with you, And Allaah measures the night and the day. He knows that you are unable to pray the whole night, so He has turned to you (in mercy). So, recite you of the Qur'aan as much as may be easy for you. He knows that there will be some among you sick, others travelling through the land, seeking of Allaah's Bounty; yet others fighting in Allaah's Cause. So recite as much of the Qur'aan as may be easy (for you), and perform As-Salaat (Iqaamat-as-Salaat) and give Zakaat, and lend to Allaah a goodly loan, and whatever good you send before you for yourselves, (i.e. Nawaafil non-obligatory acts of worship: prayers, charity, fasting, Hajj and 'Umrah, etc.), you will certainly find it with Allaah, better and greater in reward. And seek Forgiveness of Allaah. Verily, Allaah is Oft-Forgiving, Most-Merciful." [Al-Muzzammil (73):20]

Narrated Abu Musa:

The Prophet said, "The example of guidance and knowledge with which Allah has sent me is like abundant rain falling on the earth, some of which was fertile soil that absorbed rain water and brought forth vegetation and grass in abundance. (And) another portion of it was hard and held the rain water and Allah benefited the people with it and they utilized it for drinking, making their animals drink from it and for irrigation of the land for cultivation. (And) a portion of it was barren which could neither hold the water nor bring forth vegetation (then that land gave no benefits). The first is the example of the person who comprehends Allah's religion and gets benefit (from the knowledge) which Allah has revealed through me (the Prophets and learns and then teaches others. The last example is that of a person who does not care for it and does not take Allah's guidance revealed through me (He is like that barren land.)" [The Book of Knowledge Volume 1, Book 3, Hadeeth 79]