Surah 79. An-Naziat, Ayah 3

At all times there are errands of mercy and blessing and errands of justice, which the angels are prompt to execute by order of Allah. There are three features of this, thus giving the third, fourth, and fifth points. (3) Their movement is compared to that of gliding or swimming (sabhan). In xxi. 33 this verb is applied to the motion of the celestial bodies: they all "swim along, each in its rounded course". Cf. Shakespeare, Merchant of Venice: "There's not an orb which thou behold'st, But in his motion like an angel sings, Still quiring to the young-eyed cherubims". (4) In hurrying on their errands the angels press forth as in a race. (5) And thus they promptly execute the orders of their Lord.