Why did God create Satan even when he already known that Satan will be corrupted by evil?

Answer 1

Why does he create humans, that he knows wont believe in him? God gives us free will.

Answer:

God didn't create Satan, He created Lucifer, perfectly: "...thou wast perfect in thy ways from the day that thou wast created, till iniquity was found in thee... thou hast corrupted thy wisdom by reason of thy brightness..." (Ezek.28:15-17).

In granting free-will to His creation, there is opportunity for "righteous character development"... or great evil. That's the chance He took in the creation of the angels. God didn't know whether or not Lucifer or any of the other angels would corrupt. He only knew it was a possibility.

There is no other way to develop character... righteous or otherwise. Parents cannot hand their children decent moral character. They can only teach them right from wrong, be a good example to them... and hope they make the right choices in life.

If all God wanted was perfect obedience without any hassle, the angels would have been mindless pre-programmed robots. And so would we.

With the exercise of free-will comes unique, diverse and interesting personalities in everyone, molded and shaped by their personal experiences and perceptions.

And what's even better... due to Satan's corruption, moldable, flesh and blood man gets to benefit from the lessons God is allowing him to teach us, as we make our foolish choices in the flesh with an opportunity to be redeemed from it when the lessons are over. That choice, too, is ours.