Art thou not aware of thy Sustainer through His works? —
how He causes the shadow to lengthen towards the night
when, had He so willed, He could indeed have made it stand still:
but then, We have made the sun its guide;
and then, after having caused it to lengthen,
We draw it in towards Ourselves with a gradual drawing-in.
Al-Furqan 25:45, tr. Asad
This discipline and rough treatment are a furnace
to extract the silver from the dross.
This testing purifies the gold
by boiling the scum away.
Rumi, Mathnawi I:232-233, tr. Helminski