The Quran

۞ إِنَّ رَبَّكَ يَعلَمُ أَنَّكَ تَقومُ أَدنىٰ مِن ثُلُثَيِ اللَّيلِ وَنِصفَهُ وَثُلُثَهُ وَطائِفَةٌ مِنَ الَّذينَ مَعَكَ ۚ وَاللَّهُ يُقَدِّرُ اللَّيلَ وَالنَّهارَ ۚ عَلِمَ أَن لَن تُحصوهُ فَتابَ عَلَيكُم ۖ فَاقرَءوا ما تَيَسَّرَ مِنَ القُرآنِ ۚ عَلِمَ أَن سَيَكونُ مِنكُم مَرضىٰ ۙ وَآخَرونَ يَضرِبونَ فِي الأَرضِ يَبتَغونَ مِن فَضلِ اللَّهِ ۙ وَآخَرونَ يُقاتِلونَ في سَبيلِ اللَّهِ ۖ فَاقرَءوا ما تَيَسَّرَ مِنهُ ۚ وَأَقيمُوا الصَّلاةَ وَآتُوا الزَّكاةَ وَأَقرِضُوا اللَّهَ قَرضًا حَسَنًا ۚ وَما تُقَدِّموا لِأَنفُسِكُم مِن خَيرٍ تَجِدوهُ عِندَ اللَّهِ هُوَ خَيرًا وَأَعظَمَ أَجرًا ۚ وَاستَغفِرُوا اللَّهَ ۖ إِنَّ اللَّهَ غَفورٌ رَحيمٌ

Muhammad Asad

BEHOLD, [O Prophet,] thy Sustainer knows that thou keepest awake [in prayer] nearly two-thirds of the night, or one-half of it, or a third of it, together with some of those who follow thee.¹ And God who determines the measure of night and day, is aware that you would never grudge it:² and therefore He turns towards you in His grace. Recite, then, as much of the Qur'an as you may do with ease. He knows that in time there will be among you sick people, and others who will go about the land in search of God's bounty, and others who will fight in God's cause.³ Recite, then, [only] as much of it as you may do with ease, and be constant in prayer, and spend in charity,⁴ and [thus] lend unto God a goodly loan: for whatever good deed you may offer up in your own behalf, you shall truly find it with God - yea, better, and richer in reward. And [always] seek God's forgiveness: behold, God is much-forgiving, a dispenser of grace!

Lit., "of those who are with thee". With this concluding passage, the discourse returns to the theme of the opening verses, namely, the great spiritual value of praying at night.
Lit., "count it", i.e., the length of your vigil.
This reference to "fighting in God's cause" has induced many commentators to assume that the whole of verse 20 was revealed at Medina; that is, years after the rest of the surah: for, the principle of "fighting in God's cause" (jihad) was introduced only after the Prophet's hijrah from Mecca to Medina. This assumption must, however, be dismissed as unwarranted. Although there is no doubt that jihad was first sanctioned during the Medina period, the sentence in question is clearly expressed in the future tense: "in time there will be" (sayakun) - and must, therefore, as Ibn Kathir points out, be understood as a prediction of future circumstances. With all this, the above passage stresses the necessity of avoiding all exaggeration even in one's devotions.
For an explanation of the term zakah - of which the above is the earliest Qur'anic instance - see surah 2, note 34.