You have made mention of a subject in your question that refers to a contradiction in God's commands in the sense that He, on the one hand, forbids mankind from prostrating anyone other than God, and on the other hand He Commands that the same prohibited prostration should take place!

In reply to above misgiving, we may first raise a question as follows:

If a father tell his son not to use to his car for unhealthy recreations and later he requests him to drive the car to drop a respected guest back at his home, is there any contradiction in these two sayings?! Without doubt, your answer is in the negative as there is no contradiction in these two statements of the father because the eight necessary conditions that have to be available in order for a contradiction to take place are not available.  Hence, in the said case, if the son does not obey his father turning to the first request as an excuse, he is not justified and fair people would not accept his excuse.

For this reason, if God announces that a Sajdah which is a sign of worshipping is not permissible for anyone other than Me and then He commands His angels to bow down and prostrate before Adam, we should not take these two statements as contradictory to each other. In fact, disobeying Him and not fulfilling His command should be considered as an offence and we must, therefore, be sure that Iblis (the Satan) was ejected from the realm of divine servitude because of disobeying the divine command.

All what was said was based on the supposition that God forbade His creatures from prostrating for anyone other than Him before commanding the angels to prostrate. It is interesting to know that such a prohibition did not exist before and that prostration was not considered to be forbidden in the previous religions also because it was a sign of respect not worship.

It is only on this basis that the Sajdah of Yusuf's father and brothers in front of him was not considered to be abominable[1]. There are many verses in the Holy Quran about Sajdah for God[2] but you cannot find any verses forbidding prostration in an absolute way for anyone other than God, though it might be out of respect only. The verses that somehow imply prohibition of Sajdah for anyone than God are restricted to certain cases such as the Sajdah for the moon and the sun which may be considered as worshipping them.[3] Later, during the advent of Islam and because Sajdah was no longer considered as a sign of respect and it had turned into a symbol of worship only, therefore the religious leaders and the infallible Imams (a.s.) forbade their followers from doing Sajdah for anyone other than God.[4] For further information in this regard, read answer 3357 (site: 3807).