The Quran

وَما أُمِروا إِلّا لِيَعبُدُوا اللَّهَ مُخلِصينَ لَهُ الدّينَ حُنَفاءَ وَيُقيمُوا الصَّلاةَ وَيُؤتُوا الزَّكاةَ ۚ وَذٰلِكَ دينُ القَيِّمَةِ

Muhammad Asad

And withal, they were not enjoined aught but that they should worship God, sincere in their faith in Him alone, turning away from all that is false;¹ and that they should be constant in prayer; and that they should spend in charity:² for this is a moral law endowed with ever-true soundness and clarity.³

For this rendering of hunafa' (sing. hanif), see surah 2, note 110.
Since the term zakah has here obviously a wider meaning than the obligatory tax incumbent on Muslims (which, as its name indicates, is meant to purify their income and their possessions from the taint of selfishness), I am rendering the above phrase in the more general sense of "spending in [i.e., practicing] charity".
As regards the connotation of "moral law" in the term din, see note 3 on 109:6; the qualifying noun al-qayyimah (in the genitive case) has here the same meaning as the adjective qayyimah at the end of verse 3. The above definition of moral law outlines, in a condensed form, all the basic demands of true religion: a cognition of God's oneness and uniqueness and, implicitly, of man's responsibility to Him; a turning-away from all false concepts, values and dubious beliefs, all over-estimation of oneself, and all superstition; and, finally, kindness and charity towards all of God's creatures.