Surah 13. Ar-Ra'd, Ayah 15

The expression yasjud ("prostrates himself" or "prostrate themselves") is a metonym for complete submission to His will (Zamakhshari), that is, to the natural laws decreed by Him with regard to everything that exists. According to most of the classical commentators, those who submit to God willingly (i.e., consciously) are the angels and the believers, whereas the deniers of the truth, who are "not willing" to submit to Him, are nevertheless, without being conscious of it, subject to His will. However, in view of the subsequent reference to "shadows" it is logical to assume that the relative pronoun man relates in this context not merely to conscious beings but also to all other physical objects, whether animate or inanimate - i.e., to "all things and beings that are in the heavens and on earth". (See also {16:48-49} and 22:18 .)

I.e., the varying lengths of the shadow projected by any material object depend on the position of the sun in relation to the earth; and since the earth's rotation around the sun is - as everything else in the universe - an outcome of God's creative will, the greater length of a shadow in the morning and evening and its contraction towards noon visibly expresses the shadow's subjection to Him.

 lit., prostrate. Meaning, all beings submit to His Will.

"In spite of themselves": Satan and Evil. They would like to get away from the control of the All-good Allah, but they cannot, and they have to acknowledge His supremacy and lordship over them.

Even the Shadows-creations of the Imagination, or projections from other things and dependent on the other things for their existence, as shadows are to substance- even such shadows are subject to Allah's Laws and Will, and cannot arise or have any effect on our minds except by His permission. The Shadows are longest and therefore most prominent when the sun is level, and tend to disappear as the sun approaches the zenith. But even when they are longest and most prominent, they are still subject to Allah's Will and Law.

Notice that the original of what I have translated "whatever being" is the personal pronoun man, not ma. This then refers to beings with a personality, e.g., angels, spirits, human beings, and possibly other things of objective (not necessarily material) existence, as contrasted with their Shadows or Simulacra or Appearances, or Phantasms, mentioned at the end of the verse. Both these Beings and their Shadows are subject to the Will of Allah. See notes 1825 and 1827.

"Prostrate themselves": the posture means that they recognise their subjection to Allah's Will and Law, whether they wish it or not.