Sujud

What would be the point of sujud, usually, but not accurately, often translated 'prostration'? During an act of sujud the person faces the direction of the one being honoured. Now, if one were to do sujud to Allah then we might expect Allah to be on Earth. As Muslims do sujud towards the 'house', the Ka'bah, we might expect Allah to reside in it, were we to believe in it. In Surat al-Baqarah the angels do sujud to Adam, who was presumably in front of them. When Yusuf's parents (but see: Qur'an Error: Did Joseph's parents go to Egypt?) did sujud to him they would have done so in front of him.

S 12:99-100 And when they entered upon Yusuf he put his parents up and said: Enter Egypt, if Allah wills, secure. And he raised his parents upon the throne and they fell down to him doing sujud. And he said: My father, this is the interpretation of my dream before. My lord has made it true. And he did good to me when he took me out of the prison and brought you from the Bedouin life after the Devil had incited between me and my brothers. My lord is nice to what he wills. He is the knower, the wise.

But if Allah isn't on Earth, why would the founder of Islam look up when desiring a different qiblah? Regarding looking up, see: Hadith - The Book of the Prohibited actions - Riyad as-Salihin -

S 2:144 It may be we see the turning of your face to the sky so we turn you to a qiblah that you will be pleased with. So turn your face towards the Sacred Mosque and wherever you are turn your faces towards it. And those who were given the Book know that it is the truth from their lord. And Allah is not unaware of what they do.

In S 67:16 and 17 we read: Have you felt safe from him who is in the sky not to cause the Earth to swallow you when it undergoes commotion? Or have you felt safe from him who is in the sky not to send a tempest against you? Then you will know how a nadhir is.

'From him who is in the sky'. So Allah is not (usually) on Earth.

The founder of Islam at one time did sujud towards Jerusalem, because the Jews did, but the Jews would have originally done so on account of the belief that God's presence was there in the Temple. On the change of the qiblah: The Change of the Qiblah